YujiKiri

YujiKiri is the slash ship between Eugeo and Kirito from the Sword Art Online (Alicization) fandom.

Canon
Kirito and Eugeo are best friends from separate worlds who were also lost childhood friends that later reunite again.

They were best friends as they were young and quickly become best friends again when they meet again as young adults: not realizing that they've known each other for a long time but carrying that sense/feeling throughout their friendship.

Eugeo was facing a bleak life, forced to a lonesome inescapable job and feeling guilt and helplessness until he met Kirito. Kirito listened to his troubles and taught Eugeo how to wield a sword, which has changed his life significantly--and Eugeo notes that he's been waiting for someone like Kirito to come into his life.

Being with Kirito has done wonders for his self-esteem and Eugeo admits on multiple occasions that Kirito brightens his day, even saying that he´s the light of his life or that it was destiny that they met. They end up traveling together and referring to each other as partners.

Throughout the story they develop an insufferable bond of which they cannot live without each other, such as them telling each other that they'll be together forever, that they're always there for each other whenever they wanted, and so on. They do everything together, even bathing and sleeping in the same bed.

While one comes from a virtual world whilst the other comes from reality, They have been brought (up) together and established a bond that has been as meaningful as any other human connection.

Mainly being in a relationship with Asuna, Kirito is implied to have romantic friction with Eugeo throughout the Alicization series and even after into the next series: Unital Ring.

The two share very intimate interchanges in the novel. Kirito continuously refers to Eugeo with iterations of cute and/or beautiful, his features fine & gentle--and uses a lot of similar expressions to how he talks about Asuna. For instance: He refers to Asuna's eyes as "chestnut" while Eugeo's eyes he calls "sparkling emerald". He even says that he “got lost in his eyes he forgot he was in a virtual world,”. These tender-like descriptions and quotes continue on, their romantic behavior and feelings more clearer in the Light novel's narrative---most notably stating that Eugeo and Kirito were to have powerful, unnamed feelings in their chests when they see and/or speak to each other.

A quote from Kirito in the light novel depicts him claiming that he regards Eugeo on the same level as Asuna, perhaps even closer: as he found himself sharing his deepest secrets quicker with Eugeo than he did with her. These affectionate dialogues are however mostly exclusive to the novels, as the anime didn't/couldn't adapt them. Regardless, they are still quite affectionate in both: as the anime tries to convey it visually through Eugeo blushing and making their skinship look more intimate.

The topic of love is brought up in general between them a lot, especially in the later half of the story--where they may have to part from each other and where the major antagonist of Alicization tries to pry into Eugeo. In the end: he gives himself and his love to Kirito and lives inside his heart.

Much of the series’ content have supported this ship, as well as words through official sources. The mainline canon of YujiKiri can be found in the SAO Light Novels and Anime--however the anime does leave most of their moments out or does not execute it as evidently romantic as the source material, so it is advised to use the LN's as main guide. Although, the two games SAO Unleash Blading and SAO Lycoris would be just as important to the canon: as they are direct adaptions of the LN's and even expand on them further, with extra scenes/flashbacks/etc. SAO Unleash Blading  (Old name: Alicization Rising Steel)  has a few side story events that expand on their time in Walde Farm, Zakkaria Garrison, and their 2 years at the Academy, which were not shown in the anime, and some of the scenes are exclusively to this game. For instance: the main questline chapter 11 has a dedicated anime cutscene of them training in their first-year of school. It also had a special voiced cutscene where Eugeo and Kirito mention their time as Garrison Guardsmen in Zakkaria among many other story quests. As of now, SAOUB is the only media that really covers these 3 arcs, usually being skipped--even in the manga.

SAO Lycoris is an adaption of Alicization with an alternate, rewritten ending: as it shows how the story would go  if Eugeo didn't die.  Lycoris follows everything with some original additions like characters, story arcs and worlds and also gives us scenarios that could've never happened with his death: such as meeting and getting along with Kirito's girlfriend: Asuna. Lycoris also reveals some small details/funfacts: like how Kirito used to play with Eugeo's face as he slept.

SAO Lycoris even adds in a special story DLC called Myosotis, which is heavy with YujiKiri content, as this is a journey for Eugeo and Kirito that practically started from his nightmare of losing Eugeo from the fight with Administrator. This DLC has been highly praised among fans as it has really deep development between them, such as being told that they might just be more-than-friends, and that Kirito would like to invite Eugeo to meet his family in the Real World.

Aside from the games, there are a few side novels that are bonus stories to Alicization:


 * Distant Journey, which is a story that takes right after they left Zakkaria Garrison to travel to Centroria, spending their time together in a lodge.


 * 32/33 is where Eugeo and Kirito graduate from Swordscraft Academy and become Integrity Knight trainees, with the titles Synthesis 32 for Eugeo and Synthesis 33 for Kirito. They have to try and appease Administrator.

The latter title is a fun AU spin-off, whereas Distant Journey is more tied to canon that fills in a gap.

Alicization
 Childhood  The story starts off with Eugeo and Kirito as children. They both have the Sacred Task of cutting the Gigas Cedar together, a giant mythical tree that sucks up energy and takes centuries of lumberjacks to cut. They already seem to be the best of friends, making bets with each other and playing around, tickling each other.

Kirito is shown to be more energetic in this world and they are very close with eachother. In SAO Unleash Blading it is revealed that they like to come over to eat dinner together and that Kirito cheers him on whenever he was scared. Kid Kirito also looked after Eugeo when he's sick, placing an ice-cooled hand on Eugeo's forehead when he had a fever, as confirmed in SAO Lycoris: Eugeo's 3rd bedscene event. He even describes Kirito as a "Rascal with a big heart".

The anime often shows Kid Kirito giving Eugeo a big bright grin in the ending songs and flashbacks: which can be taken as that Eugeo really loves his smile, as he can't seem to stop thinking about it.

Their days go by peacefully, But then, when their other friend Alice breaks the Taboo Index and gets taken away is when they fall apart. They get abruptly separated--Kirito getting ejected out of the Underworld and gets all memories and ties to it deleted, and Eugeo grows up alone--never knowing Kirito.



However, circumstances has lead to Kirito going back into the Underworld---and they meet each other again when they're older.

 Grown-up Villagers 

Kirito woke up in the middle of the forest and was lured by the sounds of Eugeo's axe: gripping his chest as the sound gave him a warm yet regretful feeling. He walks all the way to the source of the sound, completely drawn to it.

When they see each other at the Gigas Cedar, many feelings seem to arise. In the anime, they lock bewildered eyes for quite a while, and in the novel: Kirito goes on to point out Eugeo's fine--gentle features, and bright, warm eyes. When they sit down to talk: the novel eventually mentions that Kirito got so lost in Eugeo's eyes that he forgot that this world was a creation.

Eugeo also finds himself opening up to Kirito so mysteriously easily: He shares his regrets with not being able to save Alice: which is his deepest secret---and says that he doesn't know why he would share this with someone he'd just met, stating to Kirito: "It just feels like I've known you forever." We also later learn from Selka (Alice's little sister) that Eugeo stopped smiling until he met Kirito: he showed himself as depressed and avoidant to the Rulid residents, whereas he was constantly smiling and even bursting in laughter when getting to know Kirito under the Gigas Cedar. These were early signs of Kirito being special to him.

Later in the story: Eugeo and Kirito got into a fight with a band of Goblins in the End Mountain ice caves, and Eugeo sacrifices himself to protect a wounded Kirito who was cornered and about to receive a fatal blow. As Kirito runs towards a tossed-aside Eugeo on the ground, he holds his hand: and they start to have an epiphany about their childhood together. Eugeo smiles and exchanges a few words before he faints, and Kirito who's filled with a sudden new determination: starts going on an onslaught--completely forgetting and/or ignoring his wounds. When he has dealt with the Goblin leader and forced the band to retreat, he asks Selka to heal Eugeo: even if he has to give his lifeforce to do so.

Kirito almost dies by allowing himself to be completely drained for Eugeo's sake, if it wasn't for the soul of Alice appearing to assist. In the anime we see Kirito faint and fall on top of Eugeo, but in the Light Novel as well as SAO Lycoris--it is said that Kirito had carried Eugeo on his back and walked all the way to the village.

After a few days resting from their wounds, they go back to cutting the Gigas Cedar. Kirito asks if Eugeo remembers the exchange of words that he gave him back in the cave, about the promise they made as kids: to live and die together. Eugeo claims that it was some gibberish brought from his fading consciousness, but with closed eyes and a soft smile: tells Kirito that he truly felt like they've had a life together.

The novel narrates that Kirito watched the serene air around Eugeo for awhile before taking his turn to cut the tree, but asks to use the blue rose sword instead of an axe. When Eugeo sees how easily Kirito can carry the sword now that he's gained strength from the Goblin fight and sees that the sword was able to dent the tree, he stares in shock before praising and giving him all kinds of questions. In the light novel, Eugeo asks him about his sword skills and what kind of occupation Kirito had to be this good.

Eventually they have a conversation about why Eugeo didn't try learning to wield one too. He says that swordwielding is pretty exclusive to guards and warriors, that the Taboo Index forbids people from having multiple callings, and also tells Kirito that he's always been weak. Kirito however sees that there is a spark in Eugeo--as well as the guilt and frustration that built up through out the years, and as he watched Eugeo grimacing and glancing away in silence, he thought to himself: "Hang in there, Eugeo. Don't give up. Don't give in to what binds you. Take a step...take your first step. You're a swordsman."

Then, Kirito narrates that Eugeo looked up as though he heard him, with his pristine shining eyes, and he asks Kirito to teach him the sword, to become strong and retake everything he's lost. Kirito was extremely moved when Eugeo said this, as the novel states that something powerful welled up in his chest, and that he had to fight it down to remain control.

Kirito smiles and extends a hand, promising to train Eugeo and cheekily says that it'll be harsh. Eugeo finally relaxes, and takes his hand. He jokes back that the hard teaching is just what he hoped for--before sinking down and muttering something about this moment being something he truly wanted for his whole life. He dips his head with teardrops falling and leans his forehead into Kirito's shoulder. Kirito was caught by surprise, and as Eugeo speaks again, the novel states that he felt his whisper through his body more than heard it.     This scene was slightly changed in the anime--where it cut out Eugeo leaning on Kirito's shoulder and them embracing, but it has been adapted in the manga, and they moved the "waiting for you for 6 years" quote much later, after they've cut down the tree. Their conversation about swordskills has also been moved and altered in the Anime, where Eugeo asks him after Kirito proves his worth for the village guardsman/gatekeeper Zink in the early episodes.

After Eugeo cut down the Gigas Cedar, the village throws a huge night celebration party. The boys enjoy the feast and even joined in on a dance. When the village chief asks Eugeo what he will choose to do next, Kirito slightly panicked that he'd choose to stay with his family as a farmer but he answers that he wants to become a swordsman, and makes plans to leave towards the central city together. Kirito is relieved, and before he goes to sleep he apologizes to Asuna in his head, stating that he has a new mission: to live in the Underworld, go to the capital with Eugeo, and rescue Alice.


 * Walde Farm

After leaving Rulid Village and taking a branch of the Gigas Cedar with them, Eugeo and Kirito traveled on their own. They stayed at whichever cave they could find, hunted animals, and picked berries to eat--in which Kirito had few moments of almost poisoning himself, and getting scolded by Eugeo for it.

At this point they are close. There's been times where Eugeo felt homesick or guilty but Kirito allowed him to stay optimistic. They eat and sleep together and it's also revealed in 32/33 novel that Eugeo and Kirito bathed in the rivers together, with Kirito being a bit nervous about undressing for the first few times as he wasn't used to being this close around men--while Eugeo was unfazed.

After a while, they went to live at a farm, as that was better than just wandering around. The farm was owned by a family called Walde, who hired Eugeo and Kirito for work. They had a pleasant time at Walde farm, with a nice family and peaceful days. They slept together in the shed and shared a bed of straw, sometimes they joined for dinner, and Kirito would throw pranks at Eugeo or compliment him so he'd take over his chores. They stayed there for a few months up till the Zakkaria Swords Tournament began, earning some pocket money and training in the meantime when they could.


 * Zakkaria Garrison

After ending in the top 5 of the Swords Tournament, Eugeo and Kirito were nominated to be Guardsmen in Zakkaria. They stayed there long enough till they could be recommended and do entrance exams for Swordscraft Academy.

During the Swords Tournament, Kirito protected Eugeo from a sly contestant: Zerome, who purposefully tried to injure them by upsetting a pair of horses who could trample them. Luckily due to their experience from Walde farm they were able to calm the horses down. There isn't much known or covered about their time as Garrison Guardsmen aside from occasional mentions in the Light Novel's monologues, but it sounded like they also had a pleasant time there.

SAOUB did make a few original gaurdsman scenes for it later on however. In Eugeo's Social Mode: "Giving Back"  (later listed as Archive-B Adventure 1-2),  Kirito offered to take over Eugeo's night shift so he could rest, which deeply moves him. In either of the two endings: Eugeo will blush and be indebted to Kirito, offering to pour his heart into a homemade meal as thanks or tell him that he makes him feel "a certain way", everyday. This flusters Kirito and makes him blush furiously, trying to hurry Eugeo to bed in a panicked frenzy: but returns his smile.

It's also revealed in a special cutscene during the game's 2nd anniversary that Kirito often went shirtless when they were at the Garrison, and Eugeo had to remind him that they were now at the Academy where girls could see them. In the ENG localization Eugeo exclaims: "it's so taxing being your friend", but in the JP audio he clearly says "mattaku, mitete harahara suru yo", which roughly translates to: "Geez, the sight of you makes me nervous..."

 Swordscraft Academy 

They're notably the closest in this arc, being very domestic and happy. Kirito especially has become very playful and touchy-feely, and sometimes his teases have a bit of a flirty undertone. This arc is also where the really accustom themselves to calling each other "partner".


 *  1st year: Primary trainee 

It's been 2 years since they traveled together. In the novel, Kirito narrates that Eugeo's body has grown--but mentions that his eyes were the same as they met: warm and bright. Eugeo says that time really flew ever since they've entered the Academy together, and couldn't feel more blessed to be in it. At this point they've really been together at the hip. As first-years, Eugeo helps Kirito out with his homework a lot: often doing study sessions with him and sometimes bringing food from the cafeteria. They sleep in the same dorm and in the same bed, albeit separately in a bunk bed. Eugeo often takes his time to wake Kirito up, acting like his personal alarm clock: demonstrated in the anime and also gained a special illustration in SAO Unleash Blading.

Even though they are both being coached by Elite Disciples--(superior 2nd-year students), they still get away from them to spar with eachother. Eugeo still considers Kirito to be his true mentor, and admits that he´s his one-and-only swordsmaster during their exam rehearsals in SAO Lycoris. Kirito also confesses that he´s always been thinking and waiting to train with him like the old days.

In SAO Unleash Blading's  "The Bond Residing in My Sword"  story, Eugeo admits that Kirito has been a shining light to him, bringing peace to his sleepless nights, and tells that he would do anything to help him back. Kirito realizes that even if he ever misses his home, he'll always have Eugeo to comfort him and have his back. After confirming their mutual trust and loyalty for eachother they actually both started to grow bashfully silent and visibly blushed.

It's also revealed in SAO Lycoris that Kirito used to play with Eugeo's cheeks as he slept when they were first-years. He poked them to kill time on sleepless nights, and possibly his homesickness aswell. Eugeo noted that he occasionally woke up with his cheeks tingling in the mornings--and that it only stopped once they became second-years: as they gained their own separate bedrooms.

---

During the time where they were nearing their graduation, they have another heart-to-heart at night. While planting Zephyria flowers in the schoolgarden as a gift to Kirito´s mentor, Eugeo gets sad about the possibility of Kirito leaving him after finding Alice and going home. He informs him about his worries and his own shortcomings--and Kirito was taken aback a bit, not having considered the thought, nor did he see Eugeo as flawed.

In the light novel: As he sees Eugeo tremble with sadness, Kirito thinks to himself that Eugeo was infact admirable for leaving the village to follow his own path: reciting words of encouragement in his head: ''“You are strong. You’re the one who made the decision to leave your home, in this world bound by laws and rules.”'' He placed his palm on Eugeo and hoped that the energy would flow into him like it did for the flowers.

In the anime: Kirito gives affectionate sigh and pats his back as he sits down next to him, reassuring Eugeo that he wouldn't just abandon him even after all is done. Eugeo speaks his reliefs, and Kirito stands up and puts out his hand. Eugeo smiles and takes it, allowing Kirito to pull him up and simultaneously handshaking on a promise to stay together, no matter what.

At their graduation party Eugeo gets drunk and fell asleep on the sofa. Kirito was actually the one that carried him back to their dorm and tucked him into bed, even changed his clothes.
 *  2nd year: Elite Disciple 

As they become Elite Disciples, Kirito is shown to be more sassy and touchy-feely and Eugeo bickers with him like they're a married couple. This is also where they really establish "partners" into their vocabulary and status.

They managed to share their dorm space together as they are ranked the 5th and 6th. Kirito almost didn't get to be paired with Eugeo as he was originally ranked 4th, but due to his low grades he was put down. They both were grateful to be together again, and Kirito admits that school has never been this fun for him--and that it was all due to Eugeo, as quoted in his homescreen voiceline in SAOUB.

(more to be added)

 Grand Cathedral 

In this arc their feelings become more complex as this is the point where they might have to part and where they have to make hard choices. We get to see a lot of pining and their thoughts about each other really starts to spill. This arc also confronts the topic of love. As Kirito spends his time in jail, the Light Novel showcases Kirito reminiscing about his time in the Underworld and how much he had enjoyed it compared to Aincrad and being with Asuna & Co. Everyday was so fun that he had almost forgotten about them, and if that was the case: then that would be a betrayal, and that this peace breaking punishment is just what he deserved. Yet, he couldn't help but be attached to (the beauty in) this world and the people he had met, admitting to himself that he loves the Underworld and the people in it.
 *  Cathedral Convict 

(more to be added): jailbreak, jail monologues, library, separation, red rose sword, confession & heart

War of Underworld
War of Underworld is the sequel to Alicization. In the aftermath, Kirito has been shown to be completely paralyzed, unable to talk or walk---almost lifeless. It is explained that Kirito poor state is due to inflicted mental self harm: very likely implied to be due to Eugeo's death. He clings onto Eugeo's sword all the time, even seen sleeping with it.

The anime toggles in on how important Eugeo is to Kirito, and as if to make it blatantly obvious: Kirito is saved by Eugeo and Eugeo only in World of Underworld (Part 2.). Desperate from grief, Kirito tries to take his own life because of Eugeo’s loss, even though Asuna is there. Even in a coma, the power of his own girlfriend is not enough to awake him from his grief and despair as he proceeds to attempt to rip out his heart and essentially commit suicide after remembering memories of Eugeo and him dying in his arms. The only thing that wakes him up is Eugeo, he needed to be forgiven by Eugeo to want to live again because he’s his reason to live. The two share a final boss battle where its Eugeo that helps him overcome his enemies and save the Underworld, even in death.

And even at the end, where Kirito had to erase his memory after being stuck in the Underworld for too long: he still remembers Eugeo---seeing him and hearing his voice in his dreams.

 Moon Cradle 

Moon Cradle is an interquel of War of Underworld and Unital Ring. It dives into the 200 years that Kirito spent in the Underworld. SAO Unleash Blading has adapted some of the story. This arc has not many but a few notably bittersweet YujiKiri moments, in flashbacks and memorials. (more to be added)

Unital Ring
The story arc next to Alicization is Unital Ring. It is very new and still ongoing, currently only in Light novel form, the arc starts from SAO Light Novel 21. Diving back into the Underworld, now 200 years in the future: We get introduced to an Eugeo-doppelganger who calls himself Eolyne. This is where Kirito’s feelings gets very mixed and brings out a lot of things out of him. It also traces back to alot of YujiKiri's moments.

In this new era of the Underworld, Integrity Knights have now been replaced by Integrity Pilots, with Eolyne being appointed as the head commander. With UW's new era came different rules, which Kirito had been apprehended for abnormalities--however Eolyne and his staff had come to bail him out of the detention center and they personally get acquainted.

Kirito spirals from seeing his late friend, and Eolyne is intrigued as he picked up that Kirito had the same power(levels) and the ruler of UW 200 yrs ago: the Star King, Kirito.

As possible threats are looming over UW, Eolyne and Kirito have to work together, while their curiosities for each other grow.

More about Unital Ring and Eolyne will be covered in a later section: #Eolyne & YujiKiri.

Side Stories
As said before, SAOUB and Lycoris have some event stories that branches out on the canon lore, But there are also some written bonus novels like: Distant Journey, a novel by SAO creator Reki Kawahara that focused on Eugeo and Kirito just after they left Zakkaria Garrison and before they attended Swordscraft Academy, and 32/33, which is initially an Integrity Knight YujiKiri spin-off, also written by Reki.

Both of these stories were given as bonus to the anime DVDs.

 Distant Journey 

 (more to be added) 

 32/33 

32/33, also known by both the fans and the creator as CrabCakeverse, is an AU where they graduate from the Academy without being sabotaged by Humbert and Raios: who have been poisoned by giant monster crabs during a trip. Because of that, they never broke the Taboo Index and were able to graduate and get accepted as Integrity Knight apprentices at the Central Cathedral. They decided to resolve all the conflicts by making all residents and enemies talk to each other over tea and their peace offering: cake. It's also as a means to spy on their warfare plans.

32/33 was part of Reki’s mini drabbles--(Material Edition 28 and 29) but later branched out and extended to it’s own comprehensive series. It’s distributed in 3 chapters: IF YOU WERE HERE, IF YOU WISH IT and IF WE COULD WALK TOGETHER.

Both of Distant Journey and 32/33 has been translated to read by GSImenas, which you can read on his blog: dreadfuldecoding.blogspot.

Gameverse
Most of the games play in non-canon universes, but they can reveal actual character facts and lore, and there are actually two games that do follow Alicization's real setting & storyline: These are SAO Unleash Blading and SAO Lycoris.

SAOUB starts off in the Ice Caves from anime episode 3, while SAO Lycoris starts off in their meeting underneath the Gigas Cedar from anime episode 2. If you want to get into these two games then please make sure you have watched anime episode 1 first for missing context. SAOUB recaps a bit about the previous episodes whereas Lycoris doesn't.

SAO Alicization Lycoris
SAO Lycoris is technically an Alicization reboot/expansion pack where Eugeo lives from the Cathedral Arc. Everything is taken from the original with the addition of new character Medina. Regardless, she does not make too much appearance up till where the original Alicization ends, nor change much to the story.

In Lycoris, Kirito remembers his childhood with Eugeo a little bit sooner; after fighting him in his synthesized state, and instead of having Eugeo transformed into a giant sword to fight Administrator, he fuses with the blue rose sword.

It's shown in the prologue cutscene that Eugeo was about to lunge towards her, and Kirito reached out to grab him in the nick of time. He tells Eugeo the words that was originally in the novel monologue after his death: "You blamed yourself for not saving Alice. But half of that regret should've been mine to shoulder." With that, the sword-formed Eugeo gleams and allows Kirito to use him.

 (more to be added: system control panel/fried fluctlight, anti cedar task force, meeting asuna, eugeo's bond missions&bed scenes, recollections, myosotis) 

SAO Unleash Blading
Mostly a re-telling of Alicization with recaps of the first 3 SAO seasons. There are a few extra exclusive YujiKiri stories though, For instance: the main questline chapter 11 has a dedicated anime cutscene of them training in their first-year of school, Other story events that expand on the lore (specifically Swordscraft Academy) are: "The Bond Residing in My Sword"  and " Kirito and Eugeo's Style" . There's also the social mode stories: ' ("Giving Back" & "An Odd Feeling"). ' SAOUB is also the only media so far to have covered their time in Walde Farm as well.

The main attraction for SAOUB however is definitely the homescreen voice lines and their (paired) game units. Eugeo is heavily implied to be talking to Kirito in his home screen voice lines and vice versa, and reveals more personal details about them and insight in their usual antics with each other.  (More to be added) 
 * Eugeo has some romantic standard voice lines where he blushes and says "Your eyes are really pretty." & "Can we go somewhere quiet? I want us to be alone..."
 * The night-time voice lines reveal that Eugeo and Kirito like to stargaze together. One notable line is where Eugeo visibly blushes, saying: "I could see the same stars back in Rulid, but they look different here somehow. I wonder why that is...?"
 * During Tsukimi (Japanese Moon-viewing holiday) Kirito will blurt out "The moon looks really pretty" while blushing. That quote is actually an old japanese way of saying I love you so he quickly says that he didn't mean anything by that, but he still keeps his smile and blush while saying it.
 * in 2021 a special paid offer Pajama Eugeo unit was added and is heavily implied to have been sleeping next to Kirito, and also has a lot of very sweet voice lines about him.
 * Halloween Eugeo quotes Kirito's line "Stay Cool" for his incarnate Attack.
 * New Years 2022 Eugeo and Kirito are implied to be playing Hanetsuki (Japanese New Years Batminton) with each other.
 * 2nd Anniversary Integrity Knight Eugeo has a special partner skill that reflects their swordstance in the anime opening. (ADAMAS.) His voice lines also talk about cooking dinner for Kirito among many other tender lines.

Other console & mobile games
 SAO Hollow Realization 

Eugeo gets summoned to Sword Art: Origin/ Ainground as an integrity knight with no memory. He befriends Kirito.

 SAO Fatal Bullet 

Eugeo as a GGO player. It seems somewhat connected to Hollow Realization’s Eugeo as Kirito already seems to know him and asks why he hasn't transported to his original world, however they do not recall prior experiences so you don’t need to know anything from that game to get into Fatal Bullet.

As Eugeo is a DLC character he has minimum connection to FB's story, the most you get from him is from interacting with him in the hub and unlocking his bedscenes.

Mobile game SAO Memory Defrag does have a few stories about FB Eugeo however.

SAO Memory Defrag

Eugeo gets summoned to ALO as a friendly integrity knight with no memories. Though there are some storyquests that follow Alicization’s canon.

 SAO Integral Factor 

Mobile game where Eugeo meets Kirito in Aincrad.

 SAO Arcade 

Collab games

 * SAO vs Accel world
 * Crossing Void
 * Shironeko / White Cat Project x SAO

Moments
 Signs of Love & "tight feelings in chest" moments: 


 * There are two times where Eugeo makes a statement about Kirito giving him feelings in his chest/heart, first of which was: at the Cathedral when he thought he had lost Kirito and has a monologue in his head that says describes an "emotion he cant even name"--that describes it to be painful, yet wistful and sweet. (In the anime this is nuked and replaced with him smiling and blushing at Kirito while tearing up.)
 * The second was after Kirito's heartfelt speech in the SAO Lycoris DLC (Myosotis). In Myosotis, The two watch the stars together while sharing a blanket in the desert. Kirito asks Eugeo if he could stay by his side forever--which seemed to have stuck with him ever since. After that, Eugeo later goes on to tell Silica that he felt something in his chest and that he would  fall for Kirito if he were a girl. 
 * Later on in Myosotis the entire group of girls question if Kirito and Eugeo could get so close to the point where they could be more than friends. Leafa agrees that they do act awfully close lately. Silica retorts at first, but later remembers and confirms that Eugeo had the look of a girl in love when describing that night with Kirito in the desert.


 * In the SAO Light novel, When Eugeo asked Kirito if he could teach him the sword: Kirito felt something indescribable inside that he had to try and fight down. After Kirito agrees, Eugeo leans into Kirito's shoulder and softly tells him that he's been waiting for someone like him to come into his life (for six years). Kirito gently embraces him and blurts out that they were surely meant to meet each other. He didn't know where these words came from but it felt absolutely right.  (The hug was cut from the anime and changed to Eugeo saying that it was destiny that they met after cutting the Gigas Cedar. It has been adapted in the Manga however!) 


 * During the Cathedral arc when Eugeo was separated from Kirito, he goes on to think about both Alice and him. The light novel translated and localized by Yen Press quotes this: "My most beloved person. That would be Alice, the girl who was taken by an Integrity Knight before my eyes eight years ago.  ...And while it might not the same type of love , I also had a partner, a friend as important to me as Alice. Kirito." He also goes on to describe Kirito's hair and eyes as significantly&affectionately as he does with Alice in this monologue as well as noting Kirito’s boyish/mischievous smile.
 * When Eugeo finally reunites with Kirito in the Cathedral after getting separated--he blushes and cries absolute tears of joy. The Light novel even goes to tell "Something deep inside him throbbed with an emotion he couldn’t even name." and that it was "gentle, wistful and sweet."
 * Eugeo defies death and the law of god for a moment to help Kirito defeat Administrator. His strong feelings for Kirito lead him to wake up and create a sword out of his own blood---an ability that only the moderators in this world can do. After that, he affectionately goes to call Kirito "My hero." in response---Kirito in the light novel goes on to say:  The cold emptiness at the center of my breast evaporated in the midst of blazing heat. 


 * "Love is not something you seek, it's something you give."...were one of Eugeo's last words to Kirito as he passed on his life and love to him.


 * The Eugeo that lives inside Kirito's heart later comes in War Of Underworld (part 2. ep 8) to say: "If you didn't want to leave (the Underworld), it wasn't for your own sake, It's because you love the people you've met here." the Light Novel & SAO Unleash Blading Eugeo even goes to add "....And perhaps me."


 * In Memory Defrag story event "A Rest Day For Swordmen": Tiese notes that Eugeo might love Kirito with the amount of times he talks about him.  (see #Trivia.) 
 * In the prologue of Myosotis DLC, Kirito says that he'd want to get stronger in order to protect Eugeo. Asuna goes on to say "You must really love  (suki) Eugeo-kun and the rest don't you." Kirito replies with "Yeah. I love all of you." This was not translated well in the localization: replacing it with "you must really have been shaken up". However, the JP audio still can be heard saying these lines.
 * In SAOUB during Tsukimi--a Japanese Moon-viewing holiday, Kirito on your homescreen will blurt out "The moon looks really pretty". That quote is actually an old japanese way of saying I love you. (Founded by Souseki Natsume, more info here) In the localization he adds "It's so romantic...". afterwards he says he doesn't mean anything by it, but we can see still see Kirito with a big smile as he blushes.
 * Kirito sounds like he was about to confess to Eugeo in the 4th chapter of Myosotis: the scene where Kirito hugs Dark Rose King Eugeo. After saying that he needs him--he sobs out: "ore wa itsumo...omae ga...itsumo..." which translates to "I always....you...always.."


 * In the last SAO Lycoris bedscene with Eugeo, he tells Kirito that remembering his childhood with him and having them reunite again means everything to him. (This was mistranslated in the localization to "im glad you're here") He goes on to say things like there was always a hole in my heart as he missed him in his life. They also hold hands in this scene.

 Flirty moments: 


 * Kirito calls Eugeo by "Eugeo-kun" sometimes, which can be and HAS been translated as "My Little Eugeo". He calls himself "Big Bro" (Onii-san) sometimes as well. It can be found in the Light novel and In SAO Lycoris. (To be added later)
 * Elite Disiciple Kirito interupting Eugeo’s lecture to Ronye/Tiese with: “Eugeo and I have opened our hearts to each other too.”
 * In one of the recollection events in SAO Lycoris, Kirito admits that he has grown attatched to his Night Sky Blade sword ever since Eugeo gave it it's name. When Eugeo gives his reasoning on why he called it like that: Kirito starts to call him poetic and romantic, as well as dreamy. Eugeo starts to stutter and get really flustered at that.
 * Kirito letting out a smug low chuckle when he hears that Eugeo had been desperate to be taught the sword by him, and in a rather suggestive tone asks him: “Is that so, Eugeo-kun?”
 * Lycoris: the part where they are primary trainees: where Eugeo tells Kirito that he’d help him whenever he’s in trouble because they’re friends. Kiri just inappropriately responds with: “Oho…Eugeo-kun is so gentle…as expected from my greatest mate."
 * Kirito winked at Eugeo in a SAO Lycoris cutscene.
 * "Once you agree to something, you never complain about the details. I like that part about you, Eugeo-kun..." - Kirito in the 32/33(Crabcake novel) novel
 * "You might've swept me off my feet" - Fatal Bullet Eugeo
 * In SAO Lycoris's 2nd major story DLC: Matricaria, Eugeo calls Kirito by "Onii-chan" as a joke (in the localization it's changed to "Kito") which makes Kirito audibly and excitedly gasp while muttering "that actually doesn't sound that bad."

 Pining/Yearning & Touchy-feely moments: 


 * Eugeo had shown himself to be sad about the idea of Kirito going back home---twice. Once at the Academy and second at the Cathedral. Kirito pats his back and puts an arm around him to reassure him. He visibly blushes at the second.
 * When they were separated in the Cathedral during the aftermath of the fight with Alice, they both thought of each other and admitted to themselves that they felt lonely without one another. (Light Novel-only)
 * "If i asked you to go to the dark territory with me" (more to be added)
 * In the 32/33 if novel: Eugeo leans Kirito's shoulder and falls into his lap while they're on a sofa. Kirito plays with Eugeo's hair and hums while they sleepily speak. Eugeo eventually holds Kirito's hand.
 * Kirito Slept next to eugeo on a sofa in sidestory novel distant journey and covered them a blanket.
 * Carries and tucked eugeo into bed(more to be added)

(more to be added)

Quotes
Eugeo: - "I didn't believe in destiny at all. But...Kirito, I've always been waiting. In this forest, for the past six years, for you to come." -  'SAO Alicization Anime (2018), episode 5

“His green eyes wavered, brimming with the deep sadness of loss, and I was so absorbed in it that I forgot this whole world was a creation.” - Kirito, 'SAO Light novel vol.9: Alicization Beginnings, - localized by YenPress

'''It was simply a given that we were always together, and although I didnt always think about him, I felt oddly lonely when we were apart. ...No--it wasn't that simple. Here in the Underworld, the ultimate virtual realm, I’d finally found the very first person of my gender that I could truly call a best friend. It was a bit embarrassing to admit, but that was the plain truth of it." - SAO Light novel vol.13: Alicization Dividing - localized by YenPressKirito:' Thats right. Eugeo and I have opened our hearts to each other, too. I can eat slice of pie at dinner, and he'll just chuckle and let me get away with it. -'' SAO Light Novel vol?: Moon Cradle, ch.?

'''Next to appear was black hair, still tousled from battle. Then two eyes darker than the night sky beyond the windows and yet brighter than the stars.' - Eugeo, 'SAO Light novel vol.14: Alicization Uniting, - localized by YenPress'' '"Love is not something you seek, it's something you give." -' Eugeo, SAO Alicization anime (2018) episode 24''

"If you didnt want to leave this world, it wasn't for your own sake. It's because you love the people you met here....and probably me." - Eugeo, SAO Light Novel vol.18: Alicization Lasting & SAO Unleash Blading

."Once you agree to something, you never complain about the details. I like that part about you, Eugeo-kun..." - Kirito in the 32/33 (Crabcakeverse) novel

"It's only recently that blue roses have become available for people to buy. Just coming across them is something like a miracle....Kind of like me and Eugeo." - Kirito/Kazuto to Alice in SAO Memory Defrag story event: "Memories of GGO/UW"

 (more to be added): Lycoris quotes, Memory defrag quotes, WoU quotes 

Symbolism & Subtleties
Kirito and Eugeo intentionally or not are regarded as queercoded, specifically bisexual. There are quite a handful of hints, some minor and some highly evident.

One of such is Kirito's dualwielding--which has been a known japanese slang for Bisexuality (Ryoutoutsukai) or as westerners could call it "Swing Both Ways". This may seem a bit of a joke but when you look at how close Kirito is with both Asuna and Eugeo it seems very plausible.  (More evidence about that can be found in the next section: #Asuna & YujiKiri.) 

Other factors that play into Kirito being bi-cirious is the way he had treated/reacted to men in the former seasons & volumes, and the way Kirito obsesses over (Eugeo's) muscles.

The other queer hints can be found in the Flower Language (Hanakotoba)--or just Flower symbolism in western terms. Eugeo's blue rose motif symbolizes "True love, unattainable/impossible love"---which we can definitely find back in him: he is kind and purehearted, and he deals with anxiety of unrequited love. Also, in general: Roses (Bara) symbolize homosexuality in Japan.
 * In 1st season of SAO where he doesn't shrug off Klein's flirt/confession but returns with a compliment when they part, in 2nd season GGO where he poses cutely for a group of men, in the light novels where he describes men with complimentary details: demonstrated with Sugou and Eldrie.  (See more detail in #Trivia.) 
 * In their first year at SwordCraft Academy, Kirito scans Eugeo's body when standing and walking next to each other: noting that Eugeo is more firmly built now but still has the same "gentle features" and warm eyes. At the same time you acquire a new homescreen voiceline in SAOUB for Kirito that says: "Wow, is it just me or have you really been getting jacked up?" Its also in the final Cathedral arc, where he narrates "Eugeo's muscled body" when he was about to fuse with the memory shard.
 * In 32/33 Kirito looks at Eugeo's body while they're bathing, revealing that Eugeo used to be fine with being naked around Kirito in Rulid up until the Academy where he subconsciously covers his slash wound around the stomach. Before getting out of bath, Kirito goes to touch his shoulder--stating in the narrative that it's: "hard-but-not-too-muscular".
 * The muscle scanning/touching is also demonstrated in SAO Lycoris 3rd Eugeo bedscene.
 * This habit also continues in Unital Ring: where he stares & wonders about Eolyne beneath his cloak: stating that he call tell his body is well-built and that he wants to feel how hardy his shoulder is.

A Red rose symbolizes romance--- and the final battle includes Eugeo fusing his blood and his sword to create a Red Rose Sword--for Kirito to use.

There's also at the last episode of the War of Underworld anime, where Asuna brings Kirito in the hospital a signature bouquet of  3 blue roses . This is very specific, as Blue roses are no doubt representative of Eugeo, and In Flower Language: Three flowers represents the three words "I love you". There's also another easter egg in anime episode 11: They are seen in a red rose garden, which was regarded strange by JP viewers for it's a romantic symbol. Its also oddly placed and timed---as in the Underworld lore roses are typically not likely to grow in that area for they are a high-level Sacred Arts power plant, yet they are completely surrounded by it. It also doesn't help that the episode also includes a scene where Kirito puts his arm around Eugeo and shows him blushing. The night atmosphere itself also could be viewed as romantic.

And there's the time where Kirito was shown with Pansy in the WoU anime ending, which stands for "flamboyant man". That does connect with how Kirito is described to look girly in the Light Novels, as well does his GGO avatar reflect this---not to mention that time in GGO where he posed cutely while saying "Cheer for me!". He is also quite chipper and playful around Eugeo, (and said to be only like this with him) being all touchy-feely and a tease that sometimes does a bit too much.



And lastly there's Kirito holding a Lilac in & 2019 Animejapan illustration, and he is holding it between himself and Eugeo. A Lilac means "emotions of first love" and "protection", which does speak loudly about Kirito as he's often talking about being/getting strong enough to protect those who's precious to him---and hints alot towards realizing the particular thoughts he has about Eugeo, when you look at how their first meeting went: lost in his eyes, scanning his "gentle" features, and in the later half of the story where he admits to himself that he loves the Underworld & the people in it, as well as how Eugeo was his first male friend that he felt amazed at how much he trusts and opened up to him.

With the creators adding so much to the visual symbolism throughout the anime--during specific moments, and also in this particular groom esque paired illustration--one has to wonder about the intentions.

There's also things to be said about the crossed swords in the anime opening. Kirisuna had these, and they are a romantic couple---But after the 1st Alicization opening YujiKiri gets them too, and it continues throughout War of Underworld. It does seem like a subtle hint in their development.

Eolyne & YujiKiri
The story arc next to Alicization is Unital Ring, and in this arc--an important character gets introduced. Eolyne Herlentz, a futuristic doppelganger of Eugeo. There is not much known about this character yet--as most of the Unital Ring novels have not been translated and/or published yet. However this does not stop the fanbase from seeing Eolyne as a potential for more YujiKiri.

Highly anticipated by fans to be of resemblance/connection to Eugeo via reincarnation or just by resemblance, character Eolyne is also a popular ship with Kirito. The shipname for them is Eokiri and draws many parallels with YujiKiri, but has it's own flair aswell. His first debut has to be around the Light Novel volumes 23 and 24. They meet each other in a car, and at first---Kirito didn't think all too much of Eolyne, but when he gets a closer look to his face underneath Eolyne's large cloak and hat: he starts to have a bit of an internal gay panic. The novel says that Kirito's heart started to race, that he looked at how the sun reflected on Eolyne's hair, that he traced that shape of his mouth, and that it had caused him to accidentally shoot out an incarnation blow towards the Eugeo-lookalike (which he had parried back.) After that, Eolyne introduces himself-- (using Eugeo's "boku" pronouns before quickly changing to "watashi") --and holds out his hand. Kirito gets nervous, stating that "something might come out if I touch his hand". When he does decide to shake his hand--he gets interupted by a forced log-out, which upsetted him: blood pressure rising so much that he couldn't dive back for a day.

In the Yen Press translation, Kirito scans Eolyne's body as he looked at him from the side: comparing Eolyne's slim figure to his own in his head--but monologues that Eolyne's might have well-honed muscles underneath his cloak, even though he's just glancing. Kirito even goes on to think: "I want to reach out and feel his shoulder to feel how hardy it was." In Light Novel Volume 25: The two meet again and sit down for a tea-time with pies that so happen used to be Eugeo and Kirito's favorite: Honey pies. The tea they had is also the same as Yujikiri drank during their Elite Disciple days: Kofil tea.

As they chat, Kirito gets the urge to jump over the table and interrogate and strip Eolyne, but feels like he's being held back by his aura. Eolyne eventually starts to slip his family history into the conversation: which he later comments that he usually never talks about such personal details with someone he'd just met, which parallels with YujiKiri's first meeting--Where Eugeo easily opens up about Alice, even though they didn't know eachother.

Eolyne also went through great lengths for Kirito, ordering his spawnpoint to be protected: throwing barricades in the middle of the traffic road, regardless of the inconvenience.

In Light Novel Volume 26: The two end up having to hold hands to stay under an invisibility spell. This flusters Kirito, yet also makes him sad, as it reminds him of how Eugeo’s hand felt. Eventually, Eolyne can't keep up the spell anymore and grows faint--but Kirito rescues Eolyne and holds his body up, as well as keeping him safe from any upcoming dangers. As he held Eolyne, he regards how much it feels like holding Eugeo in his arms when he died.

(More to be added: kirito tearing up, travel with two in spaceship, moon conversation)

Eolyne and Kirito switch between being close and being distant. Kirito is mainly interested in Eolyne because he resembles Eugeo and wants to find out if it IS actually him, whereas Eolyne is very formal and secretive because of his high rank but has interest in Kirito due to rumors of him being the Star King. He mostly humors Kirito,albeit he does go the extra mile for him--such as bailing him out of his apprehension, blocking entire roads around Kirito's spawn point, and studies about the Real World. In the later volumes they grow more accustomed to each other and might grow even further.

Asuna & YujiKiri
YujiKiri is regarded as the second most popular ship to Kirisuna, and from the way it gets treated/marketed and the similarities and/or coincidences the two can have: could possibly be conjectured as the male counterpart to Kirisuna. It's mostly speculation, but the story/visuals and creators/cast members do seem to support this.

Quick list of things that Asuna&Eugeo have both done with Kirito:


 * Shared bread together as they got to know each other
 * Scolded/Nagged at Kirito for being tardy/careless/etc.
 * Has their swords crossed in the anime opening
 * Watched the stars together
 * Dying in Kirito's arms
 * Calling Kirito "My Hero"
 * Shared a blanket&bed together
 * Bathed together
 * Told/Thinks Kirito that he's good with kids
 * Have their cheeks played with while they're asleep
 * Has a bonus-dvd side story novel (where they lay on top of Kirito while seated)

In the games and manga, Asuna seems very supportive of Eugeo and Kirito hanging out with each other, and she even bonds with Eugeo over the shenanigans that Kirito puts them through.

(more to be added): Lycoris & Myosotis, memory defrag

Getting intimate/Being romanceable
Other character interactions across the novel, several games, and official content poke fun or suggest that Eugeo and Kirito are more than friends. But several of the games allow Eugeo as a romance-able partner of which you can date, touch, kiss, and even sleep with. Eugeo is the only male character that continuously gets bed scenes with Kirito; paired together with a special 2D-drawn CG. You can also bridal carry him in these games. It's all incredibly lovers-like. This is not the only example of this however as even outside of romantic dating simulators Eugeo is present in universes where he never existed and continues to receive romantic and even suggestive interactions with Kirito. SAO Unleash Blading  (old name: Alicization Rising Steel)  is not shy about the tenfold of their interactions that leave them blushing, flustered, and in other romantic instances. An event in SAOUB has the two collide sensually on top of one another. Eugeo mentions that being on top of Kirito felt strange, but he was still smiling about it. There was a moment of gay panic in here for both of them afterwards.

 (to be added: the special voiced cutscene where primary trainee Kirito takes his shirt off.)  SAO Hollow Realization is even less shy about making them romantic & intimate--and is perhaps the boldest of all games so far, the first game to make them absolute gay lovers-like without much subtly or any adjustments. The dating-sim scenes and interactive functions/options are unparalleled and are straight-up leaving some innuendo's. When you reach a certain affection level and mood with him or pick the bed to rest on with him, the dialogue and voice lines becomes highly sexual.

Hollow Realization also is the one to have started the tradition of fully voiced hand-drawn CG bed(cut)scenes in all of the SAO console games. While it isn't as lewd as the touching segments, it does have a few teases like them having to huddle close to share one blanket, Eugeo feeling Kirito’s arms, and Eugeo having to stifle his voice.
 * When Bridal carrying him you'll bashfully hear him saying "omoku nai?" (Am i not heavy?) If walked to & being set down on the bed he'll say "kinjo suru yo" (I'm getting nervous...)
 * If you choose to rest in the inn bed with Eugeo as your party member--the screen fades to black, and after that you can get Eugeo's sprite to blush and say "Kochi wo.. minai de kure..!" (D-Dont look in my direction...). Implying that you've slept with him and did perhaps a little more. But afterwards he says "Mata...onegai suru yo" which roughly translate to "Do me another favor" but can be taken as "Lets do this again later...".
 * During the dating sim segments, if you put Eugeo's into an "intimate mood"-status, the reaction dialogues will change. He will say things like "Ooh, when you touch me like that I feel a little chill..." and "Enough! Youre making me all...you know."
 * In general, the noises that Eugeo makes during these interactive dating/touching-sim segments can be rather lewd-sounding, with soft "ah" sighs and whines.
 * There's a date scene where Eugeo tucks his hands under Kirito's clothes and blushes at how warm his skin is.
 * Another suggestive date scene would be where Eugeo suggest talking in private with Kirito in the inn at nights while sharing secrets. He blushes at the end, saying that he can't wait. Also at one point in this scene he tells you not to do anything to him while he's asleep, but if you agree to it you'll get negative affection points.

Aside from these, the game has some soft and sincere moments and dialogues too. They hold hands at the last bedscene, and when talked to at the inn he can say stuff like how restaurants reminded him of you (Kirito) among other things.In SAO Alicization Lycoris, Kirito makes quite forward/questionable teases with Eugeo: such as deepening his voice & letting low chuckles while teasing him and/or calling him "Eugeo-kun" (My Little Eugeo)---And while the dating segments are not as bold as Hollow Realization: the handdrawn bedscene CG in this game is also regarded as the sexiest between all of the games as it exposes the most skin.

The interactive touching/dating sim segments & dialogues are more toned down compared to Hollow Realization, being more tender and romantic. You can still put him in a certain mood-status and do things like holding hands, bridal carrying and such however. Eugeo can also make some sweet remarks when idle, like: "I feel like I belong with you." Though even when it's been toned down--there's a few bold moments in the bed cutscenes, notably the 4th bedscene: where Kirito looks at Eugeo's muscles and ends up groping his chest and touching him all over, without any promise of stopping. The whole situation and behavior of Kirito in this bedscene is regarded as rather curious.In SAO Fatal Bullet, Eugeo still seems to get treated as one of the harem options, as you get a dialogue box with: "Lets go on a date".

He has bed scenes in this game too and it contains a modest but fair amount of intimacy, The two have moments where they blush at each other, say that lying next to each other in bed feels natural, and Eugeo even says in one of the scenes: "You've might've swept me off my feet".

In SAO Memory Defrag, There´s an event that regards Eugeo as Kirito´s best sleeping partner.  (more to be added) 

Messages in Merch



 * Kirito and Eugeo share wedding ring merchandise depicting their two swords connected with a caption that they love each other and the JP voiceactors state that Asuna would be jealous if she knew of this.
 * Theres a groom figure of Eugeo released by Shibuya Scramble, and the box all have quotes of things that Eugeo had said towards & about Kirito, such as: "Our memories are right here", "Love is like watering flowers", "Let's go no matter where it takes us."
 * In a Valentines art, Eugeo is holding a spoon shaped liked Kirito's sword, suggesting that he is spoonfeeding him.
 * In an Aniplex illustration where characters show the hands & arms of whom they are close with: Eugeo's illustration only features Kirito's arm, and not Alice's.

(to be added: Groom Eugeo fig with YujiKiri quotes, Valentines art, 2020 mofumofu aniplex, Coco curry)

Creator's notes
As far as official sources coming out and talking on them, the author of SAO Reki Kawahara has continuously responded to fans about romantic, and even sexual, questions about the two, such as who's the top and who's bottom. (He even answers seriously with: "That's quite a difficult question. I'm not sure myself.")

In an interview with Eugeo's voice actor (Nobunaga Shimazaki) he confirms that Eugeo wouldn't have been synthesized by Administrator if Kirito was by his side and in his head. He also says that he regrets killing off Eugeo and that he feels sorry for Kirito: confirming that Eugeo was his first and only male friend. The fact that Reki agrees that Kirito is the one and only male companion for Kirito and probably imply that he possibly won't create another such as him drives home that what they have is special.

Reki also made several side story novels of them, but most notably is his AU/What If novel called "[32/33]" better known by the fandom as "Crab/Cakeverse." In this novel, Reki has written them to be sharing a room & bed (+ they've got the entire floor to them alone), Kirito bridal carrying Eugeo to bed, A bath scene where Kirito practically checks out a naked Eugeo, and an Eugeo falling onto Kirito's lap--with Kirito playing with Eugeo's hair as they chat. This actually draws some parallels with Kirisuna's novel "Sugary Days", where they also bathe, and lay on top of Kirito on a chair with their hair getting played with. There's also the fact that the numbers 32 and 33 in the title stands for their knight ranks---and can practically be interpreted as a pairing name.

The 32/33 Crabcake universe has garnered a fanbase, getting plenty fanarts & doujinshi's---but also seems to be starring in SAOUB's 2nd Anniversary Knight Eugeo's partner skill animation. Reki also called Eugeo "cute" in a tweet, and muses that he wants to continue writing Crabcakeverse and perhaps more Yujikiri stories.

There's also speculation that because Reki had created a lesbian-character (Yuuki Konno) for Asuna, that Eugeo might've been created with homosexual intent and/or purposes too.

Voice actor commentary
In an interview with both VAs have multiple responses of them claiming they see the two as more than friends, and continue to use romantic kanji when describing their relationship, even quoting that Asuna’s reaction would be scary.

Yoshitsugu Matsuoka (Kirito’s voice actor) says that Eugeo is Kirito’s [https://nekonotabi.tumblr.com/post/179967059910/i-translated-the-first-question-answer-on-the#%3A~%3Atext%3DJapanese%20dictionaries%20for%20%E9%80%A3%E3%82%8C%E3%81%A6%E6%B7%BB%E3%81%86%20(or%20%E9%80%A3%E3%82%8C%E6%B7%BB%E3%81%86%20for%20short)%20and%20its%20context%20means%20%E2%80%9Cto%20live%20together%20as%20a%20married%20couple%E2%80%9D. “second wife” in a magazine interview], as well does Shimazaki Nobunaga (Eugeo's voice actor) agree that they act like a married couple. The voice cast and creators also joke a lot about Eugeo being "the heroine of SAO" as well as being "Best Girl" throughout special video/radio broadcasts. This joke has seeped it's way into SAO Integral Factor april fools 2022.

Also in one of the SAO Progressive streams--when asked by the show host "If Kirito didn't meet Asuna, who would he fall in love with?" Kirito’s voice actor immediately and casually responds with "It would have to be Eugeo."

Artists & Game Developers
Abec (SAO light novel illustrator) drew quite some YujiKiri illustrations, notably the Elite Disciple drawing where Eugeo looks tenderly at Kirito. In the sketch Eugeo is noted to be blushing much harder.

Suzuki Gou, the chief art&animation director for War of Underworld--when asked which part of Kirito he took special care in drawing, answers with: "The boyish smile he only shows to Eugeo".Lycoris developers gave Kirito a DLC costume where he wears a blue&silver knight outfit and has a cape with Eugeo printed over it, supporting YujiKiri. It's interesting and quite telling how Kirito's wearing an Eugeo-themed costume while this could've been given to Eugeo himself...  (See attatched image >) 

Shironeko did a SAO collab and has dedicated an entire seperate event for YujiKiri called "My Dear Best Friend". It features several illustrations and the storymode revolves around Kirito's yearning to be with Eugeo.

Fanon

 * YujiKiri is regarded as the second most popular ship to Kirisuna, and some of the fans even enjoy them as an OT3 that they like to call YujiKiriSuna.
 * The fans like to call the JP voiceactors by "Zakki" and "TsuguTsugu".
 * There is a fanartist called FFC that draws really official looking artwork of YujiKiri. Sometimes they get mistaken for actual anime scans. FFC also just brought out a doujinshi that looks and feels just like an actual Alicization Book (aside from the R18 part.) It's called "Flee As a Bird To Your Mountain". It focuses on Eugeo and Kirito in their Academy life, but there's also a cameo reference of War Of Underworld's 2nd anime ending ("I will.." - Eir) in it.
 * There are several tumblr blogs and twitter accounts dedicated to YujiKiri, the most notable and long-lasting one being: lost-in-yujikiri on tumblr.

Trivia

 * Eugeo and Kirito's MTBI personalities (ISFJ & ISTP) are apparently quite romantically compatible. It's said that their personalities are drawn to each other because of how much they have in common to understand each other, but have enough differences to keep things interesting.


 * Kirito seems to have a sixth sense for Eugeo, knowing just when he's in trouble and having some supernatural abilities for him. This can be seen from the Zakkaria tournament arc where he warns Eugeo about Zerome, rescuing Elite Disciple Eugeo from getting beheaded by Raios in the nick of time, and in the anime when Eugeo gets puts into Deep Freeze by Chudelkin--Kirito calls out Eugeo's name. Lastly, in the Light Novel when they reunite in the Cathedral: He hears Eugeo mumbling his name and turned around with a smile even though his voice was audible from 10 mel away.


 * Kirito often (flirt)teases with Eugeo, liking to embarass him. (It's especially prevelant in SAO Lycoris.) He even uses petnames: calling Eugeo by "-kun" (The games have translated this to "My Little Eugeo") and had a few instances where he calls himself "Big Bro" (onii-san).


 * Eugeo is the only male character to get consistent lovers-like dating sim segments + bedscenes and handdrawn cgs for it, paired together with special voice lines like "I'm getting nervous..." "Don't look this way...!" "Let's do this again.../do me another favor." While you can also "date" Klein and Agil among other men from Alicization like Eldrie and Renly--Eugeo still remains the only one with a fully voice bed cutscene series and handdrawn CG.
 * Lycoris has the most bed scenes out of all the games: standing at 6. Fatal Bullet and Hollow Realization have about 3 or 4.
 * They held hands in bed. twice. in Lycoris and Hollow Realization bed scenes. They're also both from the final/last bedscenes.
 * Kirito likes playing with Eugeo's cheeks while he's asleep---a characteristic that he only really does with girls he's close with: His lover (Asuna) and his family. (Sugu & Yui) It's been confirmed in one of Eugeo's bedscenes in SAO Lycoris.
 * Kirito seems to be fond of Eugeo's muscles, often noting & giving highlight to them in the light novels monologues, and is also paying attention at them in the games. He even goes to feel them up in one of Eugeo's bed events in Lycoris.


 * There were a few times where Kirito has inadvertently confessed/said I love you to Eugeo. 1. in SAOUB during Tsukimi/Moon viewing festival where he says The moon looks beautiful tonight--which is an old japanese way of saying I love you, 2. in Alicization/War of Underworld where he admits that he loves the Underworld and the people in it, 3. In Myosotis prologue where Asuna says "You must really love Eugeo-kun and the others huh." with Kirito answering "Yeah, I love everyone", and 4. In the 4th chapter of Myosotis: the scene where he hugs Dark Rose King Eugeo, saying that he needs him--and he sobs out: "ore wa itsumo...omae wa...itsumo..." which translates to "I always...you...always..."


 * They both seem to be in love with each others eyes. Kirito describes Eugeo's eyes as "emerald", "sparkling green", "warm and bright" (Light novel) and "gentle". (SAO Lycoris). Eugeo had described Kirito's eyes as "darker than the night sky beyond the windows and yet brighter than the stars" in the light novel---and has a voiceline of: "Your eyes are really pretty" in SAO Unleash Blading. SAOUB eventually brought out new Eugeo units (2nd Anniversary Knight & Pajama) that talk about Kirito's black features as well, saying how it reminds him of the night sky and that the color suits him.


 * Its quite likely that the creators intended for Kirito to be bi, with Eugeo being his one and true bi awakening. His dual wielding is already symbolic for bisexuality--but what further supports this is this: the way Kirito can describe men in the Light Novels: going into full detail and regarding them as handsome sometimes---Plus the time in SAO's 1st season where Klein said to Kirito "You have a pretty cute face, youre just my type." And Kirito didnt freak out at it, but instead said: "That unkept face of yours suits you ten times better!" and turned with a smile. When he walks and turns back again to see that Klein left, he's visibly upset and runs away with a shimmer of a tear. Theres also something to be said in the 2nd season GGO where he poses cutely for a group of men, in the light novels where he describes men with complimentary details: demonstrated with Sugou, Vassago and Eldrie. (Pics to be added)


 * The JP voiceactors for Eugeo and Kirito (Nobunaga Shimazaki & Yoshitsugu Matsuoka) are also seen to be very close friends just like how YujiKiri is. Kirito's voice actor also does some questionable things just like him: Like being super happy whenever Shimazaki (Eugeo's voiceactor) is around and absolutely physically and emotionally drained when he's not, as well as sending Shimazaki a drunk "I love you" message for his birthday and saying that Shimazaki's best feature is his friendliness and nice smile.
 * Kirito shamelessly likes to use Eugeo's body to sleep on in Lycoris. In the chapter where they leave Rulid and were camping-out: Kirito couldn't use anything as a pillow, so he decided to use Eugeo's arm to sleep on. And in Myosotis, he asks Eugeo if he could give him his lap to sleep on.


 * In the Myosotis DLC we could've had the chance to see a hot spring fanservice cutscene with Eugeo, as the SAO girls had gotten them and Lisbeth offered them a turn to bathe: but Kirito was too busy worrying about the quest objective so we didn't. This had caused fans to spawn out several edits, fanart and comics out of it.


 * In Memory Defrag, Tiese notes that Eugeo might love Kirito with the amount of times he talks about him.
 * In Tiese’s Lycoris bed event, she asks Kirito what Eugeo's type is, and from the way he describes it she laughs, saying: "that sounds oddly enough just like you, Kirito!" implying he's Eugeo's type.
 * Eugeo is regarded as Kirito’s best sleeping partner in a mobile game event story. (Memory Defrag)
 * They hold hands often in the anime, and often passionately. This actually gets referenced later in Unital Ring, when Kirito holds Eolyne's hand in LN 26.
 * Whenever Eugeo gets fatally wounded--he somehow always seems to look at Kirito with a warm, peaceful smile.
 * Myanimelist teases this ship showing that they prefer Eugeo with Kirito.
 * Eugeo's VA Brandon Winckler made a tweet that said he took a pic with "his boyfriend" standing next to a Kirito cutout and proceeded to call him boo.
 * The JP voiceactors for Eugeo and Kirito (Nobunaga Shimazaki & Yoshitsugu Matsuoka) are also seen to be very close friends just like how YujiKiri is. Kirito's voice actor also does some questionable things just like him: Like being super happy whenever Shimazaki (Eugeo's voiceactor) is around and absolutely physically and emotionally drained when he's not, as well as sending Shimazaki a drunk "I love you" message for his birthday and saying that Shimazaki's best feature is his friendliness and nice smile.


 * In a "Kirito harem" popularity poll done by anime expo 2022, Eugeo ranked one of the highest, even beating Asuna.
 * In a "Kirito harem" popularity poll done by anime expo 2022, Eugeo ranked one of the highest, even beating Asuna.

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