Kavetham

Kavetham is the slash ship between Kaveh and Alhaitham from the Genshin Impact fandom.

Canon
"I can't deny that he's very smart. However, it's a shame that a man of such talent only pays attention to the truth itself and not to the people around him. Or perhaps this is due to an extraordinary sense of individualism, which causes a lot of problems. For example, he doesn't seem to respect his seniors... Of course, I'm not referring to myself specifically."

- Kaveh in Alhaitham's Official Introduction.

"Mainstream Sumeru academia tends to hide a certain fact from time to time, which is that for some people, talent can occasionally be more of a burden instead. Nevertheless, this view can also be but an excuse. In truth, it is your character that determines your destiny first and foremost. The aforementioned ideas are the sort that Kaveh will persistently rebut."

- Alhaitham in Kaveh's Official Introduction.

Alhaitham and Kaveh are both playable characters. They are frequently mentioned throughout character voicelines and Sumeru bulletin boards. The two first met in the House of Daena, and Kaveh had taken interest in his outstanding junior. The two were best friends before walking separate paths after a major quarrel during a large research project. Both Kaveh and Alhaitham graduated from Sumeru Akademiya, Kaveh graduating from the Kshahrewar Darshan while Alhaitham from the Haravatat Darshan. Alhaitham is still a member of this Darshan, and is responsible for documenting their findings and drafting ordinances. Kaveh is a renowned architect and independent contractor who occasionally serves as a visiting professor at the Akademiya and receives subsidies as a result. Despite being a Kshahrewar alumnus, Kaveh is still identified as the Darshan's representative and touts his association with them, which leads to him introducing himself and being introduced as someone that is from the Akademiya. As well, when referring to the Kshahrewar, he at times will use "we." In official media, he is occasionally seen at the Akademiya with what appear to be his students. When Kaveh is a visiting professor at the Akademiya, Alhaitham and Kaveh can be considered coworkers.

After Kaveh sold his old house and went bankrupt because of his dedication to completing his magnum opus, Alhaitham offered him residence. According to the Sumeru bulletin boards, Alhaitham sometimes handles Kaveh's additional fees, such as alcohol fees. Kaveh pays rent, although it’s implied that Alhaitham only collects it from him when he’s able to provide it. Alhaitham also doesn’t appear to see Kaveh paying rent as necessary to sustain their living space, but collects it anyway.

Alhaitham is only interested in studying whatever interests him, having forgone ownership of a supposed Divine Knowledge Capsule to simply study it. He also operates purely by rationality, which many people tend to find unacceptable, especially Kaveh, who is extremely fed up with him. In contrast, Kaveh operates by what he feels is right. He is a stark defender of the arts and believes that helping others is a natural course of action. This contrast has served as an important defining trait to both their characterization, backstories, and relationship, in which they are notably the exact opposite, or mirrors, of one another. Several playable characters and NPCs mention their arguments, and their intense disagreements are such that they even bleed into messages on bulletin boards across Sumeru City and Port Ormos. Messages between Alhaitham and Kaveh can be read in the Mahamata Bulletin Board, Puspa Café Message Board, and the Port Ormos Bulletin Board.

Kaveh's character trailer briefly shows Alhaitham in the beginning along with the other Sumeru characters. Alhaitham is first shown as a silhouette; the scene transitions to a side-by-side contrast of Alhaitham walking towards the Akademiya in a dark background with no people while Kaveh is running towards the Akademiya in a lighter background with people. The scene ends with the silhouette of Kaveh, establishing the concept of reflection and how the two characters are mirrors of one another.

Alhaitham’s character trailer features Kaveh, Cyno, and Tighnari gossiping about him in Lambad's Tavern. Kaveh starts off the video by continuing a conversation between the group about how Alhaitham called himself a "feeble scholar," stating that it was a bold-faced lie and proceeding to ask with interest how strong Alhaitham is, before asking Cyno whether Alhaitham is stronger than him. Later, Kaveh pointed out how he met Alhaitham during his desert expedition, wondering why Alhaitham didn't travel with him instead when it could have halved the traveling costs. Alhaitham eventually arrived to the tavern, looking over at Kaveh before he overhears what the group is discussing. His gaze lingers as he sits down next to Kaveh, and Kaveh finishes off the conversation by pointing out people should not mess with his roommate no matter how strong he is. Alhaitham tells him that he should have learned to think before he spoke and reveals that he came to the tavern because Kaveh had dragged him there, to which Kaveh replies defensively that the gossip about him had all been positive. When Alhaitham tried to provide an explanation to the confusion regarding how he referred himself as a "feeble scholar," Cyno and Tighnari both expressed confusion by the end of his philosophical lecture while Kaveh sighs that he should never have brought up the topic with Alhaitham. By the end of the video, Alhaitham comments on the wine being good and that he'll have a cup. However, there are only three goblets on the table for the other three people, respectively. It is speculated that Alhaitham may have drank and tasted the wine from Kaveh's cup, especially when it was confirmed in 3.6 flagship event A Parade of Providence that Alhaitham sometimes took Kaveh's beer without permission. However, it is also possible that he knew the quality of the wine because he frequently visits the tavern with Kaveh according to the in-game message boards and dialogue. Alhaitham and Kaveh’s character themes have similar leitmotifs.

The two share matching idles, of which is also the first occasion where two characters have matching idles. Alhaitham's second idle features him pulling out house keys, initially surprised that Kaveh's is accidentally hooked onto his, then shrugs as he put it back. In Chinese, Japanese and Korean, Alhaitham stares at the keys and lets out an irritated “Tch!” while in English, Alhaitham mutters a surprised "Wait, huh? Oh... Eh... Mmm, whatever." Zooming in on the animation shows him briefly smiling while examining the keys. Kaveh's second idle features him searching for something in his belt, panicking when he realized it isn't there, then looking to the ground, disheartened.

Monthly-Frustration-Be-Gone's description, Kaveh's complaint about Alhaitham stealing his beer, and Kaveh's Hangout story all suggest that Kaveh has the money to buy his own wine but expects Alhaitham to buy him drinks anyway. Interestingly, in both A Parade of Providence and Kaveh's Hangout, Kaveh expresses regret that he sometimes relies on Tighnari for meals and also declines Cyno's offer to help him, but has no problem relying on Alhaitham, emphasizing how much closer they are in contrast to his other friends.

There are multiple contrasts in their letters such as their mirroring birthday letter titles — Alhaitham's being titled "..." while Kaveh's is titled "!!!" and the fact that neither mentions their birthdays but instead gives the traveler advice on various topics; in his letter, Alhaitham advises the Traveler to go to the House of Daena with Paimon to encourage the latter to read more, whereas Kaveh sends the Traveler coffee beans and wishes them well on their journey.

Interestingly, unlike the majority of the other characters, neither asks the Traveler to spend time with them on their birthday in their letters. Nonetheless, they continue the trend of characters getting official content that shows them hanging out with the Traveler, such as Chinese Weibo exclusive web events and Character Shorts. As well, Kaveh mentions in the caption of his birthday art that he and the Traveler would be going to a gathering later on that day.

Both of their 2023 birthday arts take place in Alhaitham's house, with Alhaitham's taking place during the day and Kaveh's appearing to be during the night, and with Alhaitham sleeping and Kaveh awake working on a blueprint. The captions for the birthday art also imply that Kaveh let the Traveler into the house on Alhaitham's birthday, while Alhaitham likely let the Traveler in on Kaveh's.

In his letter, Kaveh mentions tasting various coffees with someone at home in order to find the best tasting one to send to the Traveler. The individual is not identified by name, and the use of "we" could imply that it was Alhaitham, who had mentioned coffee twice previously, or his friend group.

In the CN version of Kaveh's birthday post, he asks the Traveler "怎么到我们家来了？" ("why did you come to our home?"). This detail is omitted in the English version of Kaveh's birthday post.

On Genshin's Chinese medium, the short versions of Alhaitham and Kaveh’s descriptions can form a Chinese duìlián when put together.

Alhaitham: 学识, 思考及处事之道 (Knowledge, Contemplation, and Way of Comportment)

Kaveh: 体悟, 仁爱与识美之知 (Empathy, Compassion, and Understanding of Beauty)

The English version translated of these texts slightly differently, swapping Alhaitham and Kaveh’s areas of expertise with each other while describing them.

Alhaitham: The art of learning, thinking, and doing

Kaveh: The knowledge of comprehension, benevolence, and aesthetics

Kaveh's Character Stories
The following is directly copied from Kaveh's Character Stories, which elaborate on the story behind Kaveh and Alhaitham's relationship from Kaveh's perspective.

Kaveh's Character Story 3 (Mention)
"[...] At the same time, academic trends in Sumeru were disrupting his work. He began to realize that his ideals and career goals were, as a certain someone had said, not easily attainable."

Kaveh's Character Story 5
"After going bankrupt, Kaveh entered into a period of melancholy. The Palace of Alcazarzaray had ever so briefly filled the hole in his heart that had been ripped open by so many things, but it had also proved to him once again that no matter what he gave to attain his ideals, it wasn't enough. He was now directionless, and enmeshed in a world where he could not go anywhere without Mora. And yet he was accustomed since his youth to putting on a brave front, and so Kaveh was unwilling to let his colleagues and friends know that he was nigh penniless even after selling all he owned, and so he went to a tavern, where he would order a few bottles and chat to comfort himself. One bottle later, he would collapse at the table, only to wake up in the exact same position afterward.

Lambad, the tavern owner, had reserved a seat and a few free drinks for him out of kindness, and as thanks, Kaveh helped him redesign and refit the booth seating area of the tavern's second floor. He would occasionally meet friends from his Akademiya schooling days, and with them he would pretend that he was just here to drink and gather inspiration. He would spend over a fortnight in this manner, during which he would encounter that friend that he no longer called "friend." When discussing Kaveh's old friends, the current Akademiya Scribe, Alhaitham of Haravatat, will invariably get mentioned. Alhaitham enrolled at a later date than most of those his age, but his grades stood out above the rest. People didn't know who he was or where to find him normally, only that he was some student who had gotten high marks. And when his name was mentioned, even the old researchers from Kshahrewar would shake their heads and say that he was too intelligent by half and hard to get along with.

At that time, Kaveh had just parted ways with his mother and was living alone. He would meet this junior student in the library at times, and would speak to him out of curiosity, and thus did he meet the Haravatat genius Alhaitham. But time would go on to prove that wishful thinking alone does not friends make. For Kaveh quickly realized that Alhaitham, though two years his junior and admittedly both extremely talented and incredibly gifted, was also utterly different from him, whether it be in personality, dealing with people, academic direction, and convictions.

Kaveh's time in school would leave him with a great many memories, the least pleasant of which is the group project they undertook together. Each recognized the other's ability, and they decided to conduct research regarding ancient structures, ancient runes, and linguistics, with Kaveh suggesting that Alhaitham be the one responsible for selecting the topic. At first, others would take also take part in the cooperative project, but as the work progressed, the other students dropped out gradually as they could not keep up. That was the first time Kaveh realized the brutal and all-too-intuitive difference in talent between individuals. The Akademiya linked talent and resources to an extreme degree, and all here knew that. As Alhaitham liked to put it, certain matters have their upper limit determined by talent and their lower bound determined by hard work. Ordinary people and geniuses would be separated by various practical realities, and they did not have to force themselves to fit into a group they did not belong to. Kaveh, however, was resolute in his belief that this was all the result of obstacles that appeared during the process, and that wisdom should be uncovered by many people. To prevent the other students from backing out, Kaveh spent much time and effort helping them with their work, placing a great burden on his own shoulders. Alhaitham persisted in upholding the opposite view, believing Kaveh to be too idealistic in his ways — academia was not charity work, and temporary salvation would not change the reality of their differences in ability. Thus did discord arise between the two.

Finally, the day came when only two people remained working on the topic: Alhaitham and Kaveh. The disputes between them accumulated to a critical mass before exploding spectacularly. Kaveh maintained that Alhaitham was too much of an egoist, that he could be much better welcomed amongst people if he would just care about helping out more often. Alhaitham for his part pointed out that Kaveh's impractical idealism was just a flight from reality, and that it would come to be a burden on his existence someday, and the source of Kaveh's altruism was naught but his inescapable sense of guilt. At that moment, more than anything else, Kaveh felt cut to the quick by someone who was his best friend. Alhaitham had seen through the reality that he had never been able to face, causing him to feel reality's bite for the first time, a feeling that made Kaveh steadfastly declare that he regretted making friends with this all-too-intelligent person.

The two parted ways in a single stroke. Alhaitham would remove his name from that thesis, while Kaveh would rip his copy of the thesis apart in a fury — only to put it back together with deep regret. He sensed that he would not be able to change his friend, with the reverse also being true.

Afterwards, the two would later clash in academic journals several times, each criticizing the other's perspective. Before this, the "Decoding the Runes and Architectural Philosophy of the Ruins of King Deshret's Civilization" had made great progress. Its fruits on the linguistics front had filled various gaps in the grammatical logic of some ancient minor languages, allowing for the successful interpretation of many important texts. Similarly, the results achieved in architectural studies had successfully improved the load-bearing structures for some special terrain features in Sumeru, which greatly improved the lives of those living in remote regions. To encourage the project, the Akademiya had even specially designated a research site for its use. Unfortunately, lacking manpower and a united vision on the part of its primary researchers, it eventually ground to a halt.

This failed project became an unavoidable part of Kaveh's past. As the years passed, and he was beaten back by reality time and time again, Kaveh was forced to admit that his persistence born of wishful thinking was not always useful. It was only when he was rendered penniless that he finally understood the deeper meaning behind his friend's past words. A person who wished to ascend to the garden of heaven upon steps made of thin air would inevitably plant their feet on an empty stair and fall to their death. As a genius, Kaveh longed to belong in a crowd, subconsciously fearing separation from it — this was the difference between him and Alhaitham.

Returning to the matter of that table in the tavern, Kaveh was deeply shocked to see Alhaitham, who was coincidentally present to purchase some alcohol, in this place. Alhaitham for his part could immediately tell that Kaveh was in a very bad way. Having been oppressed by life for too long, Kaveh completely unloaded all his woes onto his erstwhile friend right there and then. After all, there was nowhere to hide from his problems, so what use was concealing them in front of the one friend with whom he had fallen out so acrimoniously? He would lament about a great many misfortunes that had befallen him, only falling silent when they left the tavern in the dead of night, and his eyes fell upon a place in the distance that he once called home. Alhaitham, on the other hand, listened intently to Kaveh's words, and seeing through him once more, asked him a difficult question: "How has realizing your ideals gone for you?"

Only reality can force a researcher to admit that they were wrong, but Kaveh did not know what he should consider reality. He yearned for a fantasy so perfect and beautiful that none need flee it, even if the price of this dream was losing himself. He still firmly believed that his ideals were in themselves not mistaken, and that the fault lay only in the methods used to achieve them.

People should not give up, for even if they are doing good in an attempt to make up for something, the results will still have meaning for some. Even if he could not enter that promised land of his ideals, that did not mean the radiance and the attraction of such a realm should be denied.

As for those phantasm-like realities, like how he found his homeless self living his friend's house by happenstance, or how this house, now under the Scribe's name, had been converted from that same research center the Akademiya had offered them back in the day, or how this excess academic asset would not have been turned into a residence at all after numerous transactions, had Kaveh not resolved to give it up... Or how, knowing full well that Alhaitham never did perform a good deed unconditionally, Kaveh would be plagued by guilty conscience and proactively mention helping with household chores, only to become saddled with all the domestic errands... These might be an annoyance for someone at a low point in life, but they are also proof the most unshakable part of one's past is a friend that will never change. Rationality and sensibility, language and architecture, knowledge and human feelings... Things that can never be integrated are what constitute the two sides of the mirror — indeed, of the entire world."

Kaveh's Sketchbook
"[...] Page 26: A topic application form. Postscript: 'A fine beginning. Such an intelligent collaborator is hard to come by.' Page 31: Some academic notes and architectural drawings. Postscript: 'Our views are aligned, and they are complete.' This line has been struck out. 'Our views are contradictory, but it is through contradiction that more speculation and philosophy may be born.' This line has been retained. Page 42: The cover of a thesis that has been torn up, then put together again. No postscript. Page 47: An excerpt from a school publication. The original title is unknown, and the preserved content is as follows: 'The selfish cannot understand wisdom's final destination. Though all of us might claim to have a place in this great hall of learning, we must understand that it is people, and not knowledge, that make our world what it is. Without a vessel, knowledge shall have no home. Universal values must naturally have some merit to be named such, and denying their general meaning does not mean that minority viewpoints will arise accordingly. This is the case with aesthetics. Beauty is something objective that exists in human hearts. It will not lose its value simply because some people cannot understand it. To view oneself as some mighty vessel is to fall to the narrowness of the researcher. Know that truth has never existed for the sake of individuals. The logic of the world coexists with nature, and this will not easily change whether it is interpreted as such or not. Excessive belief in the object is self-disclosure just the same, a manifestation of a lack of confidence in the subject. Moreover, one who is sufficiently self-confident will not need to constantly use plural forms of address, such as 'we.' I alone am sufficient to sustain this position — this I can assert.'" [...] "Page 112: Rent records. Postscript: 'I mean, I wouldn't call this a bad thing... But how did things turn out like this? That guy definitely wouldn't take me in for no reason and without expecting anything... But what could I possibly do for him?'"

Alhaitham's Character Story 4
The following is directly copied from Alhaitham's in-game Character Story 4, which elaborates on the story behind his cushy house and his perspective of his relationship with Kaveh.

"To live a peaceful and comfortable life, one must meet a few requirements first: Congruous personality and logic, adequate fighting prowess, a slow-paced job, and a cushy house in the vicinity of one's office.

Alhaitham has checked all the boxes above. He would never deny that no place suits him better than the Nation of Wisdom, where social capital is linked to one's academic abilities.

His current house, which is located near the Akademiya, is one of the academic resources that he gained through promising research projects. This house's story dates back to Alhaitham's student years. If his classmates still remember him, they will recall that he was not one to mingle with the crowd. As a result, he has only participated in one joint research project. Despite its eventual success, the project resulted in a huge quarrel and a parting of ways. Little do people know about Alhaitham's part in this story, though they might be acquainted with the other protagonist: The Kshahrewar architect Kaveh.

This academic incident is not very widely-known — and in truth, the tale of two geniuses falling out due to differing perspectives is an all-too-familiar one in the Akademiya. But even though their collaboration did fall through, neither of them will deny the other party's exceptional brilliance. As for their research, the Akademiya would later transfer the relevant assets to the researchers involved as per regulation.

Although the two did not continue that research, its great success in the early stage still serves as compelling proof of Alhaitham's academic ability. Later, the Akademiya even used this project, which they had forgotten to cancel, as a reference for allocating housing resources, and as such, Alhaitham was given a very decent house befitting his participation in this ingenious project. But the other contributor, Kaveh, had never approached Alhaitham regarding that allocation. It wasn't until later that Kaveh had someone inform Alhaitham and the Akademiya that he was not in want of a house and thus had no use of this property.

When next they met, Kaveh had gone bankrupt. According to Alhaitham, this former friend of his possesses a personality and values that are not congruous with his abilities. The two differ on too many things and cannot reach a consensus even today.

Allowing Kaveh to stay in this house provides Alhaitham with an interesting research topic: Legally and socially speaking, since Kaveh has previously forfeited the right to his half of this house, he should pay the landlord during his stay. However, paying rent would, to some extent, deny his contribution to the research, which contradicts the academic spirit.

An intriguing matter to consider, but Alhaitham has no interest in the answer. Thus, he has taken his broke former colleague in, collects rent as the rightful landlord, and gives his colleague some household chores. He is well aware of the dissatisfaction Kaveh might have, but it matters not to him. As far as Alhaitham is concerned, Kaveh is a familiar face, similarly lacks familial attachments, and is the polar opposite of himself as a scholar — that is to say, an excellent mirror. Human vision is limited, but it can be perfected through the presence of another genius. Taking this opportunity, Alhaitham will be able to observe other aspects of this world and thus understand more things that may have otherwise been unfathomable."

Alhaitham’s Home
Alhaitham’s home is a domain that can be visited multiple ways, primarily through one of Kaveh's Hangout endings, which is replayable.

As explained in Alhaitham’s Character Story 4, the property initially belonged to both Alhaitham and Kaveh and was allocated to them by the Akademiya as a reward for their joint participation on a successful project. However, Kaveh eventually forfeited his share of the property, leaving Alhaitham as the sole owner. An unspecified amount of time later, Alhaitham would move Kaveh in with him after learning of the latter's bankruptcy and currently serves as his landlord. Neither Alhaitham nor Kaveh refer to Alhaitham as a landlord anywhere outside of Alhaitham's Character Story, instead choosing to refer to each other as the other's "roommate." This is consistent across all of Genshin Impact's translations.

In both the Chinese and English versions of the game, Kaveh refers to the house with the term "home," such as in the Past Mementos quest during his Hangout, where the quest guide reads "Go home with Kaveh", or in his CN birthday post, where he refers to the area as "our home." In particular, CN Kaveh uses the term "家里," which is a casual way of saying "back home;" it differs from a term such as "屋子里" (in the place) or "房子里" (in the house) as "家里" specifies the home-like connection and is typically used in a familial setting. This is especially significant considering Kaveh's backstory, where he stated that he felt he no longer had a "home" — a warm place populated by the presence of a loving family.

Interior
A closer inspection of Alhaitham’s home shows numerous items designated for two people around the house. For example, there are three pots with two cups for each on the living room table (this item in the Serenitea Pot, "The Mellow Pot", originally had three cups) along with two bowls of fruit. According to Kaveh, Alhaitham never has guests over, so it is very likely that he and Kaveh spend time in the living room together. There are two "An Elegant Voice" Dutars leaning against the wall, stylish vases among the bookshelves, as well as several benches with side by side seat cushions.

There is a study with a large desk in front of a bookshelf and a floor-level desk in front of a window and within arms reach of another bookshelf. Among the various items on the large desk are a "Light of the Land of Wisdom" lamp, several books, a magnifying glass, and a sextant, while the shorter desk also has its space occupied with some books and a "Two-Way Iron" lamp. The two likely share the desks for their work, as a measuring ruler and fruit-peeling vase (known as "Star-Shaped Multipurpose Bottle" in the Serenitea Pot) can be found on the big desk while a few books and a two-seated chair can be found on the small desk. In Kaveh's 2023 birthday post, he is shown working on a blueprint on the big desk.

Also in the study, there is a double-seated bench that is positioned in front of a table with bowls of fruits, a "The Mellow Pot" set, a "The Twisting Mist" censer and a few books on it, making it likely that this may be one of the places where they eat. Alternatively, it could be another resting place, as it is positioned in front of a window and sits within arm's reach of a large bookshelf. There is also a Kamera on a tripod inexplicably situated beside the table.

There are also two short hallways leading to inaccessible doors, which are speculated to be Alhaitham and Kaveh’s respective bedrooms. It is also possible that these doors lead to other rooms of the house, such as bathrooms or the kitchen, though either way, whatever is behind these doors is un-rendered.

While it has yet to receive any official confirmation, the hallway decorations hint at the idea that the inaccessible doors lead to Alhaitham and Kaveh’s respective bedrooms; the hall leading to the first inaccessible door is where Kaveh hung his painting, implying that it is his wing of the house. On the floor, there is a red seat cushion with a gold, red and turquoise flower design, mirroring the colors of Kaveh’s outfit. There is also a broom leaning against the wall. Kaveh’s complaint that Alhaitham never helps him with the housework makes it unlikely that the broom belongs to Alhaitham.

In the second hall, there is a drawer/shelf with numerous books lined along it, along with a chest and a pot. Alhaitham is an avid bookworm while Kaveh in the Archon Quest expressed a lack of interest in physical books, making it unlikely that the books belong to him. Further supporting this idea, there are no books in the hall with the painting, despite there being books scattered everywhere else in the home.

Kaveh confirms in the event story A Parade of Providence that he has his own bedroom, which he goes into on the rare occasion someone comes to Alhaitham’s house to look for him.

Kaveh's stories reveal that he is an independent contractor, a career path he chose two years after graduating from the Akademiya and gaining experience in his field of work. However, it's unclear whether he currently works from his own design studio, as his affiliation "Independent Design Studio" would imply, or if he works from home, most likely using Alhaitham's study as an atelier. As it’s current layout, there is little physical evidence that suggests Kaveh works from Alhaitham's study or any other part of Alhaitham's house, although there is some information that implies he does at least some of his work at home, such as Alhaitham's "Goodnight" voiceover, in which he mentions Kaveh keeping him awake by hammering away at a project. His Hangout Event also implies that he creates his blueprints at home, though he is also capable of producing them on the spot by drawing them and showing them to the client using Mehrak's projection feature.

Voicelines/Character and NPC Mentions
"Did you sleep well? I hope you have a great day today. And that you don't run into someone who ruins your day first thing in the morning."

- Kaveh's Good Morning voiceline.

"I hope my roommate won't be hammering away on another one of his projects in the dead of night... Actually, I'd prefer if he wasn't home at all. I really don't want to wear my soundproof earpieces to bed."

- Alhaitham's Good Night voiceline.

"I guarantee you'll never meet anyone else who's as infuriating as him! And for the record, yes, I would say that to his face. Sure, he's smart, and sure, geniuses often come with a bad temper, but that's only half the story with him... He knows perfectly well how to appear friendly and likable to others, he just doesn't want to. If he ever gives you the impression that he doens't really have a temper, or that he's rigidly logical like a machine, then you just don't know him well enough yet. He definitely has a personality, it's just... too big a personality. Most people wouldn't get it."

- Kaveh's About Alhaitham: Temperament voiceline.

"Alhaitham helped me out a fair amount recently. If we were still as close as we were during our student days, then I'd be thanking him every chance I got. Now, though... I can't seem get a word of appreciation out of my mouth. Even if I could, I wouldn't want to give him the satisfaction. I guess you could say our relationship is something of a mixed bag these days? Honestly, with everything that's happened, it almost feels like the universe has been playing pranks on us... It's hard to make sense of it all... too much to process for one lifetime. I will say that it's not every day that you get to know someone like him — I just wish he could rein in some of the worst excesses of his personality. Okay, yeah, that's never gonna happen."

- Kaveh's About Alhaitham: It's Complicated voiceline.

"Kaveh tends to be overly sensitive about everyone and everything he crosses paths with, and he's constantly making a fuss about nothing. Maybe it's because he's too emotionally fragile…"

- Alhaitham's About Kaveh: Overly Sensitive voiceline.

"Someone set up a stand on the street saying that for each handmade keychain they sold, a child in poverty would be given a meal. Kaveh bought at least a dozen. ...This is Sumeru, where even healthcare is free. I needn't say more."

- Alhaitham's About Kaveh: Getting Duped voiceline.

"Apparently, a lot of people think he has a bad temperament, but I don't think they're giving him a fair chance. When Kaveh built a house right over a Withering Zone and created a huge mess, it ended up being a real headache for the Forest Rangers. Even so, this Forest Ranger didn't hold it against Kaveh. He even invited Kaveh to his house for a meal. Hmm, maybe it's good people like him who allow people like Kaveh to survive."

- Alhaitham's About Tighnari voiceline.

"The General Mahamatra once brought him to our place for a meal. From the moment the fruit arrived on the table, he ranted non-stop about his difficult and stubborn roommate for the entire meal. We didn't get a single word in the whole time. We just nodded along and tried to stifle our laughter. It took a lot of effort."

- Collei's voiceline about Kaveh and Alhaitham.

"He has an almost-perfect grasp of what it truly means for Sumeru to be a Nation of Wisdom. Sadly, the truth as he understands it will never be accepted as the mainstream. Hmm? He's roommates with Alhaitham? Wow... the world really is full of surprises..."

- Nahida's voiceline about Kaveh and Alhaitham.

"Kaveh is a famous architect in Sumeru. The Palace of Alcazarzaray is his magnum opus. During the initial planning, he even asked me to recommend suitable ornamental flora. I don't know why or how, but he ended up heavily in debt after the palace was completed. Alhaitham is helping out by letting him stay at his place, but... I don't know whether that's a blessing or a curse..."

- Tighnari's first voiceline about Alhaitham and Kaveh.

"Be careful of Alhaitham. I'm not saying he's a bad guy, but he purely operates by rationality, so people often find his actions unacceptable. If you don't believe me, just ask his housemate — thanks to Alhaitham, he has more pent-up frustration than an angry Anemo Slime."

- Tighnari's second voiceline about Alhaitham and Kaveh.

"I own a stall here selling drinks, snacks, and stuff like that. My food is reasonably priced. A popular choice for student meals, welcome parties, and team-building alike! And I even got the Mahamata among my clients, too! One bought a whole case of wine! [...] Haha, I actually have no idea what he does, but folks say he's a Mahamata. He was tall and looked like a guy who could hold his drink. But I couldn't tell if he bought the wine for himself or for someone else... I remember him murmuring something like "one case should be enough for an apology" as he carried the wine. ...Say, maybe he wanted to get someone drunk so that they'll forget his mistakes?"

- Shevirme, a Sumeru NPC at the Grand Bazaar

"Paimon: Ah, look! Is Alhaitham taking a nap? Traveler: Shh... You're too loud, Paimon. Paimon: Th—That's not true... Paimon was definitely whispering... Traveler: So, what do we do now? Someone opened the door for us, but who's going to wake him up... Traveler?: Paimon heard it was his birthday today and wanted to stop by and say 'hello.' Why don't we leave him a note? Paimon: Paimon... Paimon isn't going to be the one to call him! If Paimon wakes him up, he's going to start asking lots of impossible questions!"

- Alhaitham Birthday 2023 Twitter Caption (EN).

While the following voicelines do not mention either Alhaitham or Kaveh, they match in context, especially considering the confirmation in 3.6 flagship event A Parade of Providence that Kaveh usually brings home food for Alhaitham after eating outside.

"Let's not eat here. Mind if I... take it home?"

- Alhaitham's Receiving a Gift: III voiceline, triggered if he is given a soup-based dish.

"My favorites are alcohol, warm soup, and anything with cream or cheese in it. Oh, and I'll never say no to fresh fruit."

- Kaveh's Favorite Food voiceline.

Using Nahida's skill after Act V to read the mind of Panah, an NPC located in the House of Daena, would show his thoughts of how Alhaitham and Kaveh begun arguing again.

Possible Mentions
The following scenes are vague and only possibly related to Kaveh and Alhaitham.
 * Lambad, an NPC located in Lambad's Tavern, had his tableware damaged possibly in a fight between Kaveh and Alhaitham, as the new tableware in the tavern is said to be made by craftspeople commissioned by Kshahrewar researchers and patterns designed by Haravatat researchers. Given how often Kaveh and Alhaitham reside by Lambad's Tavern and how the tavern was featured in Alhaitham's demo, it is very likely the fight was between Kaveh and Alhaitham.
 * In Archon Quest Chapter III: Act II — The Morn a Thousand Roses Brings: The End of Sabzeruz Festival, the Traveler and Paimon discover a letter Dunyarzad left for them on a compilation of folk legends concerning Lesser Lord Kusanali, created from a series of interviews that she conducted in succession and wrote down. One of the stories goes: "There was this one time when I'd had a wee bit too much to drink and couldn't find my way home to save my life. Then, when I turned a corner, I could've sworn I saw Lesser Lord Kusanali. She was very tall and had the most muscular arms, and she caught me when I slipped and fell. The next morning, I found myself sleeping under a tree. I reckon that must've been her looking out for me!" The transcription is possibly from Kaveh, as he is often noted to be an alcoholic and Alhaitham is a notably muscular person.
 * Contradictions that Nahida has observed in human behavior are mentioned in Nahida's Character Story 1, one of which is that some people have a tendency to say brutal things when spending time with someone they truly love. While the translation may change the wording, the general meaning remains the same. This is an ambiguous mention, as while this description could apply to Alhaitham and Kaveh's relationship due to their tendency to argue with each other despite the fact that it is implied that they still care for each other, it is unknown how much Nahida knows about how they interact, as according to her "About Kaveh" voice-line, she had no idea they were living together despite seemingly having a deep understanding of both characters. However, she could have observed their interactions while they were out and about, as the two are known for arguing in public. Furthermore, there are no other known major Sumeru characters about whom this observation could have been made.

Akasha Pulses, the Kalpa Flame Rises
Kaveh is first indirectly mentioned in the Archon Quest when Alhaitham stated that his place was finally in peace now that he temporarily had it to himself. When Dehya questioned him on what he was speaking of, Alhaitham replied with "Oh, huh, nothing."

Their first on-screen interaction is in Act V, where they argue as Kaveh doesn't believe Alhaitham is sincere about his praise of him as a master craftsman or the possibility of Kaveh becoming a sage, as Alhaitham almost was. Kaveh dismissed Alhaitham’s sarcastic compliment, the latter claiming that it was sincere, and Kaveh responds that it’s because Alhaitham has never said anything good about him before. Alhaitham retorts by saying that Kaveh has never said anything good about him either. Kaveh then call him arrogant, which prompts Alhaitham to say that if Kaveh can't stand his personality, he is welcome to move out of his house, which Kaveh considered a threat. Alhaitham asks what Kaveh was doing while away from Sumeru, irritated that he was not there in its time of need. Kaveh is confused as to what happened while he was gone, and decides to ask around to figure out what Alhaitham is referring to as he claims he's done speaking to him.

After talking to Alhaitham, Paimon, who witnessed their previous conversation along with the Traveler, asks Alhaitham if Kaveh is his friend. Alhaitham retorted, "Do we look like friends?" possibly averting answering the question given their past relationship, and instead replies that Kaveh is his roommate, and the reason the latter seems to have so many problems is that he never listens to Alhaitham. Interacting with Alhaitham again triggers a voiceline in which he stated how he originally planned to stay in the House of Daena longer, but later decided to go somewhere else due to how Kaveh might show up again, which is a "nuisance." However, Alhaitham stayed nonetheless.

Later, in the House of Daena, the player has the option to witness another conversation between Kaveh and Alhaitham. Kaveh tells Alhaitham that the people want him to replace Azar as the Grand Sage, and Alhaitham says that has nothing to do with him. Kaveh says it's likely people without any real information were spreading rumors, and Alhaitham tells him that he hasn’t learnt a single crucial bit of information the whole time he was out there. Alhaitham tells him all the sages have been exposed and removed as Azar's accomplices, and Kaveh wonders if that was why they sent him out on a project.

Later, at Nilou's afterparty, Alhaitham mentions that he realized he "accidentally" brought both house keys with him when he left their house, but shrugged it off.

Alhaitham's Story Quest
The first mention of Kaveh occurred near the end of the quest, when Paimon nagged Alhaitham on answering her questions. However, as the timing then had been over Alhaitham's working schedule, Alhaitham refuses to further commit to work-related activity and turned to leave. When Paimon kept pestering him, Alhaitham chastised, "Are you done? Your behavior is reminding me of some other people," in irritation. Paimon angrily remarks that he is switching the topic. Later, it is revealed that Alhaitham planned on continuing the conversation in his own house.

When the trio arrives in the house, Kaveh can be found in the hallway. He greets Alhaitham and initially wanted Alhaitham to help him straighten a painting the latter had placed in the house, but stops midsentence in surprise when he sees the two unfamiliar faces in the house behind Alhaitham. Alhaitham scoffs that the Traveler and Paimon are obviously guests and that Kaveh is making too much of a fuss. Kaveh realizes that the two are not from the Akademiya and panics that there are now people who knows he lives in Alhaitham's house because he’s broke and in debt, to which Alhaitham remarks sarcastically that only now did Kaveh start feeling embarrassed about that matter. Alhaitham soon left to get the books the Traveler needed to answer his questions, leaving Kaveh to talk with the duo. Before he walked away, Kaveh angrily berates Alhaitham for leaving so abruptly.

The first thing Kaveh asks the Traveler and Paimon as they settle down is whether they're actors hired by Alhaitham to pretend to be his friends, towards which Paimon is dumbfounded. Kaveh sighs and states that the reason he asked this is because he was surprised when Alhaitham had never invited friends to his house before, given his temperament and personality. Paimon questioned Kaveh about being Alhaitham's friend, to which Kaveh replied with a smile, "Uh... not 'friends' exactly...," and later elaborates that they used to be friends, then looked away when he said that it is no longer the case. He changes the subject abruptly at that and fully introduces himself to Traveler and Paimon, asking them not to give away how he lives with Alhaitham, to which Paimon responded playfully that Kaveh must pay her in order for her to keep her mouth shut about the matter. Kaveh exasperated, pointed out that of course the duo would treat him in a way Alhaitham often does, given they are friends with Alhaitham. Alhaitham eventually returns, commenting on their loudness, and Kaveh leaves, upset, telling Alhaitham to entertain his own friends.

Kaveh eavesdrops the proceeding conversation between Alhaitham, Traveler, and Paimon. When Alhaitham commented on the humanity within humans, Kaveh comes out to sarcastically point out the irony in how Alhaitham was one to have considered humanity and emotion at all. He states that if humans aren't humans without humanity, Alhaitham might as well have evolved into another species in another decade, referring to Alhaitham's extreme rationality. Alhaitham returns the argument by stating how Kaveh may as well have devolved into a fungus, to which Kaveh answers that he'd at least be a fungus with empathy.

Clearing his throat, and seemingly just remembering that they have company, Kaveh turns to the Traveler and apologizes for eavesdropping their conversation, and Paimon tells him that a strange researcher had targeted them and brought them trouble. Kaveh worriedly asks whether they are okay, and Traveler replies that it was actually Alhaitham that the researcher had it out the most on. Kaveh instantly changes his tone and chided Alhaitham, saying that if he'd stayed indoors that day, the whole situation would have been avoided. He adds in how Alhaitham could have helped with the housework for once pointing out that his books are everywhere and unorganized. Alhaitham sighs, and points out that Kaveh has a lack of conversational skills, to which Kaveh easily rebukes at the pot is calling the kettle black. However, he glances at Alhaitham again, asking whether he is okay. Alhaitham replies that he is doing quite well, much better than the painting Kaveh is trying to hang on the wall. Kaveh becomes upset and leaves again.

Kaveh doesn't appear again until the second to last shot of the main cutscene, in which he lingers in the background as Alhaitham talks about the importance of keeping one's priorities straight. He is shown scratching his head at the painting he hung up at the beginning of the quest. Alhaitham orders the Traveler and Paimon from his house so that he can go get dinner and advises them to do the same, though he is eventually found to be chatting with Kaveh instead.

If the Traveler chooses to stay in Alhaitham's house by the end of the quest, they can trigger another harangue between Alhaitham and Kaveh if they enter the two's office. In this cutscene, Alhaitham and Kaveh discuss Siraj's incident and bicker about matters related to their jobs in the Akademiya. After Alhaitham yet again called out Kaveh's embarrassing deals, Kaveh revealed that he had took time out to clean the living room for Alhaitham only to receive such treatment. Alhaitham straightforwardly replies that Kaveh should pay his rent soon, as he plans to buy furniture with that Mora. Kaveh criticizes Alhaitham's taste in decoration, and the two begin insulting each other's skill and tastes again. Later, Kaveh circumscribes that if Alhaitham were to buy furniture, he must take Kaveh along with him. Alhaitham retorts that Kaveh only said so because he wanted Alhaitham to buy him drinks, to which Kaveh happily confirms. Alhaitham stated that the idea was ridiculous and that Kaveh would have needed to pay him back eventually. At the end of the conversation, Kaveh tells Alhaitham to tell the Traveler and Paimon to keep the secret in which they live together since he’s broke and in debt, and Alhaitham remarks that there is no need to hide the fact so carefully when Kaveh is such a lightweight that a few drinks in the tavern had him spilling out all his secrets. The scene ends with Kaveh panicking whether everyone knows that he lives with Alhaitham now and that he’s barely has mora.

Using Nahida to read Kaveh's mind in the second cutscene would reveal him panicking over how Alhaitham or other tavern owners may have spilled his secrets, and he wondered whether Alhaitham knows about his drunken scribbling. Using Nahida to read Alhaitham's mind would show thoughts over tidying books, implying that he conceded to Kaveh’s complaints about his books being unsorted.

Kaveh's Hangout
Alhaitham is mentioned several times in Kaveh's Hangout Event, and he makes a brief appearance in the route The First Ideal, and in the ending Wondrous Times.

Wealthy Merchant
Traveler sarcastically retorts against Tippu, an investor who kept being antagonistic toward Kaveh, with one of Alhaitham's lines in the Archon Quests: "You don't seem to think about your questions very thoroughly before speaking." Kaveh responds by bafflingly asking the Traveler why they tried to sound like Alhaitham.

Kaveh also mentions that the more wealthy a person is, the more miserly they are, and passive aggressively states that someone like that might remind you every other day that it’s time to pay rent, hinting at Alhaitham.

A Whole New Style
Kaveh was reflecting over Badawi's actions and how it, in some aspects, reflects his own ideology, he brings up Alhaitham and how in the many years they have known each other, they have always argued over their opposing ideologies. Kaveh recalled that Alhaitham had told him how a strong swimmer would always be dragged down by others when they run out of stamina, a fate corresponding to that of the idealists. Kaveh once again rejects this point of view, commenting that Alhaitham is the type of person that would stand by the shore mumbling "respect other's fates" while someone drowns next to him. He then hesitates, contradicting his previous statement when he compared his own fate to that of the tired swimmer and realized someone had actually helped him at his worst. Although he doesn't say who has helped him, it's implied that he's thinking of Alhaitham. Kaveh shifts the topic, and the scene ends.

Past Mementos
A drunken Kaveh had returned to his and Alhaitham's house after Traveler suggested that he could perhaps find comfort in the items his mother had left behind many years ago. Kaveh tells the Traveler that Alhaitham isn't home, so they are free to sit wherever they want.

Compared to Kaveh's attitude in A Parade of Providence in which he firmly regarded the house as Alhaitham's and expressed eagerness to move out, Kaveh doesn't mention that the house is Alhaitham's and treats it as his own.

The First Ideal
The Traveler and Kaveh enter the Temple of Wisdom, a large library containing the House of Daena and many of Kaveh's old memories from his days as a student in the Akademiya. Kaveh stated that, of the many places in the Akademiya, the House of Daena had been the most memorable, as he liked the ambience and availability of ancient physical books. He also liked his days as a student, because he could draw out his designs freely without worrying about budgeting and bringing them to life. He pulled all-nighters in the House of Daena often whenever his studies got busy.

As he walked across the bookshelves and showed one of the books he had annotated on to the Traveler, he wondered aloud why Alhaitham's handwriting had been on his book. Kaveh shrugs it off by stating that it was likely from when he worked with Alhaitham on the research project together, and proceeds to bring up that the House of Daena was where he first met Alhaitham. Many years ago, Kaveh had felt bad for Alhaitham when he saw the young scholar sitting by himself away from the other Haravatat students, looking too lazy to join them. He explains that he mistakenly thought Alhaitham was in trouble and approached him, and Alhaitham appears and finishes his sentence by commenting that Kaveh was the one in a whole heap of trouble.

Kaveh freaks out at Alhaitham's sudden appearance and exclaimed that Alhaitham would've been at the records room at this working hour, and that he may have came here just to see Kaveh making a fool of himself. Alhaitham replied that, if he had derived amusement from watching Kaveh falling into depression, he would have been entertaining himself for years. Kaveh calms himself down, and refuses to continue his story about his relationship with Alhaitham, to which Alhaitham then finishes the story for him and asks why the two had come to the House of Daena. Kaveh cuts the Traveler off when they were about to reveal that he had been feeling unwell, proudly claiming that it is a senior's responsibility to offer a friend tours of the Akademiya's architecture, and Alhaitham teasingly remarks that their next stop might be Razan Garden, as "our famed architect sure loves showing off that corner to all his friends." Alhaitham proceeds to lead Kaveh away by telling him that the books the latter had annotated were moved away by the ex-Conservator, who thought Kaveh's annotations were too long and difficult to read, enraging Kaveh and successfully causing him to storm away to the faraway bookshelves to move them back to where they were.

With Kaveh gone, Alhaitham asks the Traveler to elaborate on what they said about Kaveh feeling unwell, and they begin to discuss Kaveh's situation, as well as why Kaveh has found himself in it. Alhaitham explains that this is due to a flaw in Kaveh's personality, in that he prioritizes the feelings of others over his own, despite the fact that he, as the Kshahrewar's leading genius, should have the right to reject unreasonable demands from his clients, and would likely be respected for doing so. At the end of their conversation, Alhaitham concedes, essentially saying that they should respect the paths others have chosen for themselves because everyone is unique. When Kaveh returns, he asks if they were talking about him, and Alhaitham asks sarcastically what he thought. Kaveh retorts that it would be more interesting than talking about the files Alhaitham was sorting, before reading out an annotation thanking him for his notes in the book he found, gaining Kaveh another heart. Alhaitham remarks on how easy Kaveh is to please, to which Kaveh responds angrily, saying that he's mocking the ex-Conservator for moving his books in the first place, and that he'll have a discussion with him about relocating the books. Alhaitham questions him on why he won't move them himself, given that the ex-Conservator dislikes him and has previously referred to him as the Urchin of the Kshahrewar due to his penchant for scribbling and writing in various books. Embarrassed, Kaveh remarks that Alhaitham should not have mentioned the latter while he was there, before shifting the conversation to the doodle in the book.

The drawing turns out to be the first draft of the Port Ormos bridge, which Alhaitham doesn't seem to recognize at first, much to Kaveh's dismay, to which Alhaitham responds by teasingly asking him to explain. Kaveh offers to take the Traveler down to Port Ormos, but Alhaitham declines the Travelers' invitation to come along because he needs to finish up work before returning home. Kaveh claims that Alhaitham is incapable of appreciating art and departs with the Traveler.

Alhaitham is briefly mentioned again near the end of the route when Kaveh says that Alhaitham believes he lives in the shadow of the past due to his personality, and he disagrees with this conclusion Alhaitham reached, instead believing it's just a part of life.

Wondrous Times
One of the options after discovering Kaveh's mother's diary in Alhaitham's home leads to Kaveh and the Traveler deciding to visit Faranak's old professor Zaha Hadi for answers to what Faranak's diary password may be. Zaha Hadi had recalled Faranak's many feats, and that the former was happy Faranak had finally found a place to call home after so many years of hardship. Kaveh asked Zaha Hadi how his mother had coped with the stress, to which Zaha Hadi replied that she was not too sure, as Faranak rarely opened up to people. However, one thing Faranak stated in an argument struck out to Zaha Hadi: that it is extremely hard for artists to find people who can truly understand their ideas. Kaveh tried out "understanding" and "acknowledgement" for the diary password, but both failed. Zaha Hadi comments that Kaveh and Faranak were quite alike — both stubborn, and a little awkward. Like Kaveh, Faranak had a clear expression, and would fight for it tooth and nail, getting into many fights with her clients as a result. Such fights got better when she met Kaveh's father, who had never understood Faranak's ideas, yet stayed by her side listening to her joys and sorrows, leading to Faranak eventually choosing him instead of her many admirers in the end. Kaveh entered "companionship" as a password, and the diary opens, much to his surprise and joy. Leading away, Kaveh reads through his mother's diary.

Faranak tells of meeting "someone special", someone she didn't feel much towards at first but eventually became someone "[she] felt very happy whenever [she] got to spend time with." A drawing was attached to the diary, showing the fathers (or adopting father, in Cyno's case) of Kaveh, Alhaitham, Cyno, and Tighnari, and a note had elaborated on their friendships. In particular, the "stiff-looking couple" (Alhaitham's parents), were "unbearable." The note ends in Faranak hoping Kaveh to participate in similar gatherings one day, making many different friends as the meeting shown in the drawing had demonstrated. Kaveh then notices a note on the back of the drawing, a message Faranak specially left for him, in which she stated that, whenever he feels down, he could form connections with other people and accumulate fulfillment from spending time with them. The "positive feelings" he would get "will get [him] through the long and difficult years [...] [and] companionship is the most important thing of all." Pondering over his mother's words, Kaveh considers accepting Tighnari's dinner invitation and decides to go regardless of whether the Traveler reassures him that it's fine to lean on his friends or not.

The underlying themes of the conversations and Faranak's experiences were speculated by many fans to be extremely significant, as they perceived them as heavily resembling many elements of Kaveh's current and past life. However, in truth, there are many contrasts between Faranak's described relationship with Kaveh's father versus Kaveh's relationship with Alhaitham; As for similarities, like Kaveh, Faranak was brilliant and had many admirers, yet had been deeply troubled throughout her life due to her pursuit of her dreams, leaving her a shadow of herself. Kaveh's father, who, despite not having understood Faranak's ideas but stayed by her side throughout her hardship, had instead ultimately been the person she chose and created "home" with. While Kaveh met Alhaitham, who stood out in the crowd and became a significant part of his life during his time at the Akademiya, the same period in which Faranak met Kaveh's father and fell in love with him, they did not stay together in difficult times, as their inability to agree on anything and Alhaitham reminding Kaveh of his situation tore their once close relationship apart and kept them separated for several years after they parted ways. It would be years before they were reunited and formed a "home" together, one that is still not fully functional due to underlying tension that still exists between them.

Out of stubbornness, Alhaitham and Kaveh do not offer each other support any form in their differing opinions and paths in life, as they are shown to clash over egoism vs idealism, individualism vs collectivism, and the sanctity of the arts vs the single-minded pursuit of knowledge. At best, Alhaitham has reluctantly accepted that some people choose paths and adhere to philosophies with which he personally disagrees, but he still very openly criticizes and pokes fun at Kaveh for his pursuits and failings, which Kaveh reciprocates during their arguments.

Another key difference is that Kaveh didn't chose to make a home with Alhaitham like Faranak did with Kaveh's father. Their meeting several years later was entirely coincidental when Kaveh was homeless, and Alhaitham's decision to allow Kaveh to live with him was based on his belief that Kaveh was a necessary part of expanding and perfecting his understanding of the world, making Alhaitham the one who chose him. Kaveh, on the other hand, was shown to be skeptical of the arrangement, believing that Alhaitham would never do him a favor out of the kindness of his heart.

In short, compared to the mutually loving and supportive relationship Zaha Hadi and Faranak portray Faranak having with her former husband, Kaveh and Alhaitham's relationship is far more complicated and mutually antagonistic at times, although there are underlying implications of caring. As well, their tendency to disagree isn't portrayed as entirely negative, as it has been stated that they respect each other's academic brilliance and view their disagreements as learning experiences in order to broaden their understanding of the world, despite neither openly admitting to this to each other.

It is also demonstrated that, despite their animosity, Kaveh and Alhaitham have nonverbally accepted each other in their lives in other ways, as Kaveh has accepted his role as the person who takes care of the home and brings food for Alhaitham from his social gatherings, and Alhaitham allows Kaveh to work in the dead of night and does not disturb him, allows him to read the files he leaves out, and helps himself to Kaveh's beers. As well, in Kaveh's 2023 birthday letter, he implies that he and Alhaitham tested the best tasting coffee beans to send to the Traveler for their journey across Teyvat. All of this implies that there is some peaceful coexistence in their shared house between all of the arguing, though it remains to be seen whether Kaveh truly considers Alhaitham's house to be what he considers to be a proper "home" due to how different it is from the one he came to know, and he has yet to verbally communicate his feelings in that regard.

Throughout the first half of the ending, Kaveh had been shown often pondering over Zaha Hadi and his mother's words. Some fans speculate the Hangout to be one of the signs to Kaveh finally coming up to his end of a compromise, where he realizes the undeniable significance and lessons learned from the many years he spent with Alhaitham; however, another way to interpret this ending and Kaveh's realization is Kaveh learning from his mother to rely on others in times of hardship, which he has shown reluctance to do in his conversation with the Traveler. While this obviously involves relying on Alhaitham, it also includes Tighnari and Cyno, two other characters he is shown to be close to and who have offered him their help in the past, with him confirming that Tighnari has directly helped him before. This interpretation is directly supported by Kaveh finding a drawing done by his mother depicting his father drinking with Tighnari and Alhaitham's fathers, and Cyno's adoptive father, and all sitting in the same positions as him and his own friend group in the Hangout Memory Leisurely Gathering. As well, Faranak had also hoped that Kaveh would attend social gatherings and make many friends, suggesting that she wasn't expecting him to seek out companionship from a singular person, but many people.

When Kaveh, Tighnari, the Traveler, and Paimon arrive at Pardis Dhyai, it was revealed that Tighnari also invited Alhaitham to dinner in order to discuss Collei's future with his friends, with Kaveh expressing mild disappointment that it wasn't just a free meal, but nonetheless eagerly contributing to the discussion. Tighnari almost starts the dinner without Alhaitham when Kaveh says he won't be there, and Kaveh initially agrees before quickly changing his mind and saying they should wait for Alhaitham and chat a little longer. As Tighnari chats about Collei's upcoming curriculum, Kaveh wonders whether its complexity inspired Tighnari to invite "that guy." Alhaitham suddenly shows up, to which he shares a typical sarcastic bicker with Kaveh before entering the topic of studies. Throughout the conversation, Alhaitham teasingly butts in to Kaveh's statements, much to Kaveh's exasperation, such as when Kaveh suggests Darshans for Collei and Alhaitham remarks that he may as well list every Darshan but Haravatat. Kaveh's heart meter increases by one throughout the dinner, and the scene would transition to Kaveh drunk as he ranted about a troubling client. Alhaitham reveals that that he knows Kaveh often gets up in the middle of the night to make individual designs the client didn't request, to which Kaveh angrily tries to deny. The quest soon ends in an image of the four leisurely hanging out, with Kaveh puffing at Alhaitham. The caption to the ending reads, "The positive feelings you gain will get you through the long and difficult years."

A Parade of Providence
Both Kaveh and Alhaitham are featured in the A Parade of Providence flagship event. Alhaitham is one of the commentators and judges to the competition, while Kaveh is a contestant and representative of Kshahrewar. While Kaveh initially joined to fulfill his deceased father's dream and to use the prize money to buy a house of his own, Alhaitham joined to investigate Sachin's mysterious case half in personal interest and half on Kaveh's behalf. In the entire event, Kaveh was the only person Alhaitham had personally addressed to without dismissively cutting off any possibilities of personal connection.

In Act I, Kaveh first indirectly noted Alhaitham when he was chatting with the other contestants of the competition. When asked what he joined the competition for, he stated that he wanted to buy property, to which Paimon butted in and almost revealed that he lives with Alhaitham. Kaveh immediately coughs, lying that the case had nothing to do with Alhaitham, and explained his situation with his father. Faruzan found this suspicious and wondered whether the two are hiding something from her. Using Nahida to read Kaveh's thoughts after this conversation would reveal him thinking about moving out of Alhaitham's place.

Afterwards, when all the Swiftflies have been collected, Alhaitham declared the conclusion of the first round and immediately turned to leave. Kaveh called to him and proposes that, as him and Faruzan caught the Swiftflies together, their two points should be split between them. Alhaitham retorted that there isn't a rule in the handbook that permits this action, and Kaveh told him to just add a rule. Alhaitham refused, and Kaveh questioned that Alhaitham was standing in the way of his victory. They eventually came to the solution of drawing lots, to which Kaveh lost and had to forfeit his point to Faruzan. Alhaitham remarked that it is rare someone so unlucky in life is still so willing to draw lots to decide victory, and cut Kaveh off when the latter accused him of not understanding the situation. Afterwards, Kaveh angrily tried to catch up with Alhaitham, who had abruptly left.

In Act II, the competition took place in the desert. Alhaitham was somewhat indirectly mentioned when Kaveh was explaining Mehrak's functions to the Traveler. Kaveh stated that, as Mehrak isn't able to talk, it couldn't give him an attitude. He then shifts the conversation and talked about how he wished this season of his life ends soon. One of the reasons he gave when explaining events of his life that caused it go downhill was first meeting Alhaitham in the library.

After the competition ended, Kaveh offered to draw lots yet again, as he and Faruzan found the last Ley Line Disruptor at the same time. Alhaitham retorted that Kaveh gets caught up in things like drawing lots easily, and Kaveh protested that the former should not have made it sound as if the latter finds pleasure in bad luck. Kaveh won the draw and almost cried, as his luck had finally taken a turn for the better. Alhaitham was shown quiet and studying Kaveh, crossing his arms, and the scene ends.

Later, Aarav suggested the Traveler and Paimon to check on Alhaitham for information on the missing Sachin. They ended up coming to Alhaitham's house, where Kaveh let them in. Kaveh remarked that he typically stays in his own room when people come to see Alhaitham, as he couldn't risk people from the Akademiya finding out he lives there, although most people "have better things to do" than to "barge in here looking for [Alhaitham]." Paimon then asked Kaveh where Alhaitham was, and Kaveh snorted that all that matters to the latter is that the former is out of the house. Traveler smirks, asking whether they had a quarrel, and Kaveh revealed that Alhaitham had criticized his emphasis on seniority and reliance on luck every round to achieve victory. Kaveh acts out the argument and concludes it angrily by stating that he had had enough with Alhaitham, with the disdain being mutual between them. He expressed that Alhaitham would have to do his own tidying and cleaning of the house from now on, as Kaveh had already picked a new house and would be moving out of the house right away. Paimon shifted the topic to Kaveh's wellbeing and eventually whether Kaveh had any information on Sachin, to which Kaveh replied that Alhaitham had mentioned to him information about Sachin recently and asked him to look over his notes. Kaveh hands the Traveler and Paimon the notes Alhaitham had took, and Paimon wondered whether it was okay to read it without Alhaitham's permission. Kaveh retorted that Alhaitham had certainly been okay with taking his beer whenever he pleased, but reading his mind with Nahida would show him pondering whether Alhaitham leaving such particular notes was really unintentional. Indeed, it was revealed later that Alhaitham had intentionally been hinting to Kaveh regarding Sachin, who had connections to Kaveh's deceased father.

In Act III, the Traveler and Paimon investigated into Sachin's supposed abduction, and realized something may be wrong with the diadem, the objective of the third round in the Interdarshan Championship. Paimon realizes that some of the information aligns with Alhaitham's notes and that Alhaitham would have previously looked into the matter.

As the third round finally begins, Alhaitham continued acting as a commentator and judge, namingly noting Kaveh to be "late" in the Chinese version of the game. Being caught in between the vicious fighting among the other contestants, Kaveh stumbled upon the thrown diadem and was dragged towards the ending line. Sachin's consciousness proceeds to intrude his mind and materialize in front of him, much to the surprise of the cast and to Alhaitham's expectations. Alhaitham and Sachin engaged into a conversation that helped Kaveh realize that the latter was used as a subject of Sachin's human nature experiment, and Kaveh breaks the diadem as a result, to end the line of suffering and regret Sachin brought to the winners of each Interdarshan Championship, rejecting his status the successor to Sachin’s research in the process. Sachin's consciousness smiles as he fades away, implying that he anticipated Kaveh's rejection of him and his worldview in order to maintain his idealism. Tighnari would later point out that Sachin's choice of Kaveh as his successor was not coincidental, lending credence to this theory.

As the contestants come forth to check on Kaveh's discomfort, Alhaitham announces Kaveh as the winner of both the round and the Interdarshan Championship. Notably, Alhaitham is smiling during this interaction. For the "avoidance of doubt," Alhaitham also asked Kaveh whether it was of his true intention to donate all of Sachin's wealth. Kaveh replied that rejecting the world would achieve nothing and that he would bear the responsibility of the consequences to breaking the diadem, which would cease the pain that would have been brought to all the future generations of Interdarshan contestants. Alhaitham smiled, bringing the conversation to a personal end by commenting that Kaveh had long been aware of his own flaws and that he said well, even if the former still finds this sense of justice quite ridiculous. Kaveh referenced to his first conversation with Alhaitham in the first Act by replying that he didn't need Alhaitham's insincere praise and that the time and place was not right for a debate over personal views. Nilou concluded the scene by announcing the transition to the award ceremony.

As Cyno pays Kaveh a million mora as tribute to Kaveh giving away the incredibly rare TCG cover award, Kaveh decided to treat everyone to a meal when he realized he had enough money to cover the bills of his month. Alhaitham proceeded to disappear in the meal, and Kaveh complained that the one time he had been in a good mood to treat Alhaitham, the latter doesn't show up. While the group chatted into the night about Kaveh's choice in breaking the diadem, Kaveh gave a side comment about how it was a good thing Alhaitham wasn't there, as he would have been quick to prove him wrong. Collei remarked that Kaveh seemed to always include Alhaitham in conversations, and Tighnari adds that no dinner with Kaveh is complete without a few words on Alhaitham. Cyno then joked that Alhaitham lives rent-free in everyone's hearts, which Kaveh considered horrifying. Reading Kaveh's mind with Nahida after this conversation would show that he thought about ordering some food to bring home to Alhaitham.

The final sub-quest features the Traveler coincidentally finding Alhaitham while searching in Aaru Village for clues about the incident Sachin encountered twenty years ago. Alhaitham was reading Sachin's notes, and remarked that he would never have agreed to being a commentator if not for investigating Sachin. He then explained to the Traveler and Paimon his view on empathy, reality, idealism, and human nature, all themes heavily connected to Kaveh's view of the world and the event of his life, and while explaining why Sachin chose Kaveh to be his successor in the first place, as Kaveh was a genius that could also understand human suffering. Alhaitham would also point out that while Sachin’s research and worldview wasn’t incorrect, sometimes being correct means nothing at all, which is a statement that would be reflected in his conversation with Kaveh in When The Curtains Close, implying that he had his disagreements in Kaveh in mind when he said this.

After Alhaitham concluded his explanation, Paimon wondered aloud if Alhaitham came to Aaru Village solely for news on Sachin when he could be eating together with everyone while Kaveh was treating. Alhaitham dismissively stated that Kaveh would have packed leftovers for him if that's the case, which lined up to Kaveh's thoughts after the get-together dinner.

When the Curtains Close
If the player chooses not to inform Kaveh about the his father’s past involvement with Sachin, or failed to complete the side quest Sachin’s Article prior to obtaining this quest, Alhaitham, who researched the incident independently, will show up and inform him instead. The conversation will only become available if Kaveh is not informed, or if the player failed to complete the side quest that unlocks the option to tell him.

In this scenario, Kaveh will ask as to where Alhaitham was during a celebratory dinner he was hosting with friends, telling Alhaitham that he cannot survive solely on books. Alhaitham will remark that he doesn't recall having to report his whereabouts to Kaveh and that surviving on meals paid for by him would be more difficult than on books, much to Kaveh's chagrin.

Kaveh then mentions that he knew Alhaitham was researching Sachin, but he was surprised that Alhaitham was interested in Sachin's research due to their opposing philosophies, Sachin's being nihilism and Alhaitham's being egoism, despite finding them both equally repulsive. Alhaitham points out that Sachin's research was not completely meaningless, and that he left his findings behind after conducting large-scale experiments. He shifts Kaveh's attention after sarcastically thanking him for the compliment, explaining that he didn't come there for that particular conversation, meaning to inform him of something else.

Kaveh confirms that his philosophical debates with Alhaitham are as interesting to him as they are to Alhaitham, and Alhaitham follows up by telling him that, according to his findings, his father met Sachin twenty years ago, much to Kaveh's surprise. Kaveh realizes that Sachin's influence caused his father to go out into the desert, which is why Sachin recognized him in the first place. Alhaitham momentarily expresses some sympathy for him.

The two then debate the likelihood of a situation like this repeating itself after Kaveh destroyed the diadem, with Kaveh insisting that things won't go exactly the same way because one person's actions cannot predict the behavior of the group, and Alhaitham feeling the opposite way because Kaveh is also an anomaly in this situation, having made a choice that not many others would have. After some thought, Kaveh declares that he will not change his mind and that Alhaitham will not change his mind, causing Alhaitham to relent due to the two arguing over their opposing philosophies for years and both being equally stubborn on their viewpoints. The debate has long since moved beyond who is right or wrong.

After some hesitation, Kaveh thanks Alhaitham for informing him, which Alhaitham pretends he didn't hear the first time. This could also be interpreted as Alhaitham being surprised to be thanked because of the genuinely surprised delivery of his line, and that he was only pretending he hadn't heard it to catch Kaveh off guard.

Kaveh annoyedly repeats his thanks in a louder voice, calling Alhaitham out for pretending not to hear him, to which Alhaitham responds cheekily that earnest thanks should be expressed three times, asking him to "please" repeat it one more time.

This notably conversation ends on a lighter note than the one where the Traveler and Paimon choose whether or not to tell Kaveh about his father, with Alhaitham having distracted Kaveh from his guilt about his father’s death rather than leaving him to dwell on it.

When their conversation finishes, they will be replaced by the male and female NPC’s originally seen in the Parade of Providence preview site art that featured Kaveh, implying that these two characters were meant to represent them.

Mistranslations and Voice Misdirection
The English version of the game presents a considerable amount of mistranslations and voice misdirection that often lead to misconceptions or antagonism of the ship, primarily on Kaveh's behalf. Alternatively, it could also be seen as a different interpretation of the ship.

Unlike the CN, JP, and KR versions of the game, Kavetham in EN is significantly more sarcastic and dramatic, primarily in the voice acting. It excluded many of the tone shifts present in the original CN version of the game and, in many cases, modified lighthearted and joking themes to be more serious and sometimes aggressive. Within the scripting, a considerable portion of Kaveh's dialogue is modified in EN to include capslock or interrobangs instead of the regular question or exclamation marks in the CN script, while specific tonal emphasis and hyperbolization not present in three other languages is placed into phrases in a way that can change the connotation and themes of entire dialogue branches. Two examples of modification of scripting in which the translated script comes off more negative than the original script include:

CN Kaveh: Stop reading that annoying book — come on and tell me, what happened in the Akademiya? [...] Yeah right, it's just something you got with your authority, forget it. I came back today to hear that the sages have disappeared!
 * EN Kaveh: Just put down that worthless book and tell me what happened in the Akademiya. [...] It doesn't matter, it's probably just another thing that you used your authority to get your hands on anyway. Just put it aside. Listen, I came back today only to hear that the sages have disappeared!

CN Kaveh: He could rather have helped me out at home with the housework. Look at those books over there — they haven't been tidied for long. Since they're books you wouldn't normally read, just don't put them all outside!
 * EN Kaveh: Plus, he could have helped me with the housework for once. See those books? They've been sitting there waiting for someone to sort through them for an age. If you're not gonna read them, tidy them away! They don't belong there!

Though this is more prominently seen as localization of the script to fit comedic tropes of the West or as an alternative interpretation of the relationship dynamic, it sometimes attracted negative attention from the fandom in how Kaveh can be considered to be much more demanding, disrespectful, and negative in EN compared to the characterization in the three other languages. Indeed, fandom interpretations of Kaveh vary considerably between Asian medium and Western medium.

There are also minor differences in Alhaitham's Character Story 4 between the original CN and the EN translation, particularly concerning the last paragraph which downplays Alhaitham's closeness to Kaveh.

Original Chinese Version: In Alhaitham's view, […] who know each other from the inside out (alt trans: "by heart",  "through and through", essentially meaning that they have mutually deep understanding of each other)

English Translated Version: As far as Alhaitham is concerned, Kaveh is a familiar face.

Fanon
People had begun shipping the pair prior to Kaveh's official appearance in-game, due to information released on Kaveh’s personality and his status as Alhaitham's roommate. Fans had initially speculated that Kaveh might bear a resemblance to Kevin Kaslana from Honkai Impact, since they had similar sounding names and Alhaitham had a similar appearance to Su, who Kevin wasclose with. Many fans enjoy seeing the discussions between the two, and like the contrast of their personalities. Fans enjoy how they are prone to bickering, but much more like an old married couple than anything truly antagonistic. This is especially the case with the way the Chinese script is worded.

People had speculated about their university days and what their relationship was like then. Many people made comics of them interacting in their younger years while others came up with potential reasons as to why Alhaitham let Kaveh live with him, as if he actually disliked him he probably would not have. As more content released and the backstories behind the two are fully revealed, fans noted that the relationship is actually complex and tragic, with the two sides struggling to express their care for the other due to poor communication — Alhaitham expects Kaveh to understand the harms to the latter's overbearing selflessness through bluntness and the truth, while Kaveh expects Alhaitham to care more for the world around the latter through excessive care and anger, both of which are ineffective solutions for the stubborn other due to their completely opposite mindsets. However, as the two both ultimately lost their families (especially considering Kaveh, who lost "home" since he was young) and lack people who truly understand themselves as they do one another and have an undeniable bond from this understanding, fans and even Kaveh's English voice actor have agreed that the two are, in the end, inseparable and would likely be living together for a long time. Fans mostly looked forward to if the pair can receive relationship counselling in the future storyline, as many scenes in the story already confirmed both Kaveh and Alhaitham do worry about one another often.

It is not uncommon to see them drawn along with Cyno and/or Tighnari, as they also attended the Sumeru Akademiya. After the release of Alhaitham’s trailer, fans were delighted as Kaveh and Alhaitham turned out to be friends with Cyno and Tighnari, which matched the popular fic trope where the duos attend double dates. The release of Kaveh's hangout event also further developed the relationships between Kaveh, Alhaitham, Cyno, and Tighnari, as Kaveh's hangout event shows the fathers of these four had also been friends in the past.

Currently, the pair has amassed over 5000 works on Ao3 in the five months since Kaveh’s reveal in Act III of the Sumeru Archon Quest, making it one of the faster growing pairings to be written about in the fandom. It was originally rivaled by Cytham, although Kavetham has since surpassed it in terms of popularity and widespread fandom appeal due to the amount of official content it has received in canon. However, there are some who have opted to pair all three characters together.

Finally, due to the lateness of Kaveh's arrival in the Sumeru Archon Quest compared to Alhaitham, Kaveh has a few minor but developing ships on his end as his relationships with characters beyond Alhaitham are slowly revealed, and he has since been paired off with characters such as Faruzan, Cyno, Tighnari, and Nilou, although these ships have yet to amassed the same level of popularity as Kavetham.

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Trivia

 * Alhaitham and Kaveh may be partially inspired by Aristotle and Plato, respectively. This is primarily due to their ideologies matching that of Aristotle and Plato's (Alhaitham a materialist, corresponding to Aristotle, and Kaveh an idealist, corresponding to Plato), how their relationship matches that of Aristotle and Plato's (Plato was Aristotle's senior and teacher, and famously debates on their contradicting philosophies, corresponding to how Kaveh is Alhaitham's senior and frequently debates with Alhaitham on their contradicting philosophies), how their splash art poses match that of Aristotle and Plato's poses in the famous painting School of Athens, along with Alhaitham's many references to Aristotle, such as how he was reading Aristotle's book The Physics in Archon Quest Chapter III: Act IV - King Deshret and the Three Magi - Cry from the Eleazar Hospital.
 * Both Kaveh and Alhaitham have Dendro visions.
 * Both Alhaitham and Kaveh have bird-themed constellations; Alhaitham’s is the Vultur Volans (Flying Vulture, EN) or Tiānsǔn-zuò (Peregrine Falcon, CN), while Kaveh’s is the Paradisaea (Bird of Paradise).
 * Both Alhaitham and Kaveh have canonically wielded weapons from the Tulaytullah weapon series:
 * In the Sumeru Archon Quest, Alhaitham can be seen wielding the sword Xiphos’ Moonlight while fighting Cyno.
 * In Kaveh’s character trailer, he is shown wielding the claymore Makhaira Aquamarine.
 * In some accounts, Xiphos and Makhaira, the owners of these weapons, were lovers prior to Makhaira being sold off to become a court dancer to King Badanah.
 * Kaveh is the older one of the pair and Alhaitham's senior.
 * In Alhaitham’s Official Introduction which was provided by Kaveh, Kaveh suggests that Alhaitham has an issue with respecting his seniors.
 * In the Chinese version of Tighnari’s "About Kaveh" voice-line, he refers to Alhaitham as Kaveh’s "学弟", which translates to "junior" or "younger male schoolmate".
 * Kaveh’s fifth Character Story confirms that he’s two years older than Alhaitham.
 * Back in their Akademiya days, Alhaitham and Kaveh first met in a library, with Kaveh approaching Alhaitham first. This is how many fan arts and fics depicted their first meeting before Kaveh's fifth character story confirmed it.
 * Alhaitham and Kaveh were best friends during their days in the Akademiya.
 * Alhaitham and Kaveh have matching Serenitea furniture carpets — "Glorious Emerald Tapestry" for Alhaitham and "The Olive Grove" for Kaveh. It’s also possible that Kaveh had a hand in creating "Musing Tawny Tapestry".
 * In Chinese, these carpets are called "Pattern as Glorious as Malachite" and "Pattern as Glorious as Groves" respectively.
 * Alhaitham’s carpet appears at the entrance of the Palace of Alcazazary, the structure of which is Kaveh’s magnum opus.
 * Coincidentally, a pattern similar to the one on Alhaitham’s rug makes an appearance in Kaveh’s Dendro-infused Claymore attacks. Similarly, the pattern from the "Musing Tawny Tapestry" can be seen on the ceiling of Alhaitham’s burst animation.
 * Kaveh's pre-release chibi and Alhaitham's birthday chibi stand in the same location at opposite camera angles.
 * In the official 300,000 subscriber celebration art to KR Genshin's fancafe, an artwork of Kaveh and Alhaitham playing TCG together is shown. One detail particularly standing out to Alhaitham's character is how the invitation letter is on Kaveh's end of the table, meaning Alhaitham had been the one who invited Kaveh for a duel.
 * There was one scene in Kirara's trailer where she delivers packages to known characters across different regions. Kaveh is one of the characters, and the background used for his delivery was Alhaitham's house.
 * In the animated wallpaper to the A Parade of Providence flagship event, Kaveh briefly glances at Alhatiham and looks way. Alhaitham then does the same to Kaveh.
 * Alhaitham’s English voice actor ships Kavetham, and made a joke about it on his Twitter.
 * There was also a short period of time where Alhaitham's English voice actor and Kaveh's English voice actor switched their Twitter profile pictures to be matching icons of Alhaitham and Kaveh.
 * In an unofficial livestream with Alhaitham, Tighnari, and Collei’s Korean voice actors, Alhaitham’s voice actor described Kaveh when he was asked what he thinks Alhaitham’s ideal type is. He later spoke in Alhaitham's voice, "Waiting for me, Kaveh?" in a gentle, flirtatious tone.
 * In the 3.6 Chinese livestream, Tighnari's chibi blushes when he talks about Kaveh having to move to Alhaitham's house.
 * In the Japanese version of the patch 3.6 livestream in which the voice actors commentate the stream while being in-character, Alhaitham is given the task of reporting core parts of Kaveh’s personality, such as describing Kaveh’s "delicate and sensitive heart" and his ability to understand different human emotions.
 * One version later, in the Japanese 3.7 livestream, Kaveh's voice actor introduces Alhaitham's banner. Kaveh hesitates and chuckles nervously when he mentions Alhaitham, contrary to his calm mood when introducing Kazuha.
 * In the English version of Tighnari’s "About Alhaitham" voice-over, he refers to Kaveh as Alhaitham’s "housemate" and is so far the only character to do so. This is because in American English "roommate" and "housemate" tend to be used interchangeably despite the terms having different implications regarding one’s living situation in other languages. In Chinese and Japanese voice-lines, he instead refers to Kaveh as Alhaitham’s "roommate".
 * The last quest in Alhaitham's Story Quest, right before Alhaitham invites the Traveler to his home, is named after a classic romance novel Pride and Prejudice. The same applies to the Chinese version of the game.
 * Both Alhaitham and Kaveh's 2023 Birthday Arts take place in Alhaitham’s Home. This can be gathered through the chair and desk designs, the floor pattern, and the indirect hints towards Kaveh or Alhaitham letting the Traveler and Paimon inside.
 * The Japanese translation of Alhaitham’s 2023 Birthday caption is the only caption that leaves out the allusion to Kaveh letting the Traveler and Paimon into their home. This is because with the text and the hashtags, the caption would have exceeded the 140 character limit. "You’re being too loud, Paimon", which was likely spoken by the Traveler, was left out of the translation, as well.
 * Alhaitham and Kaveh are one of the only pair of characters to mutually introduce the others playable variant. The only other characters to share this distinction at the time of writing are Cyno and Tighnari, who indirectly introduce each other.
 * Coincidentally, their names on their introduction cards are also mirrored, as Kaveh’s is positioned to the left, while Alhaitham’s follows the usual trend of being to the right.
 * As revealed in Kaveh's Hangout, Kaveh often shows his friends around Razan Garden. Razan Garden was the place Alhaitham's first trailer took place in, and is also Kaveh's favored set in the Serenitea Pot.
 * Alhaitham and Kaveh's house was originally a research facility built by the Akademiya for them to work in. It was converted into a proper house after Kaveh relinquished his rights to the properly.
 * Interestingly, Alhaitham's Character Story treats it as if it was always a house, and that Kaveh declined because he didn't need a house at the time. It is unclear whether this is a continuity error or a deliberate omission to demonstrate Alhaitham’s tendency to leave out certain information when recounting events, as he’s done before in his dialogue.
 * Faranak, Kaveh's mother, took issue with aspects of Alhaitham's father's personality, ironically calling to mind criticisms Kaveh has of Alhaitham.
 * Interestingly, despite being Kaveh's longtime roommate, Alhaitham has yet to acknowledge Kaveh's assistant, Mehrak, following the trend of other Sumeru characters associated with Kaveh never mentioning it, with the exception of Nilou, who only briefly refers to it as "Kaveh's toolbox" and to Kaveh as it's "owner" in a cutscene.

Variations
Kavethaynonari refers to the ship between the two, Cyno, and Tighnari