YujiKiri

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

Canon
Yujikiri comes specifically from the Alicization series: the 3rd season of SAO.

Kirito and Eugeo are best friends from seperate 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 eachother for a long time but carrying that sense/feeling throughout their friendship.

Kirito taught Eugeo how to swordfight which has changed his life significantly--and Eugeo notes that he's been waiting for someone like Kirito to come into his life. They end up traveling together and referring to eachother as partners. In their journey they go through a lot together: working in a farm together, participating in a tournament, working as guardsmen, enrolling into a prestigious academy, and more.

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 arc: Unital Ring.

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

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The two share very intimate interchanges in the novel. Kirito continuously refers to Eugeo with iterations of cute and/or beautiful, 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 in the narrative.

Their behavior and feelings are more clear 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 eachother. 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 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 novel and anime, as the anime tries to convey it visually through Eugeo blushing and making their skinship look a bit more intimate.

The topic of love is brought up in general between them a lot, especially in the later half of the story, where the major antagonist of Alicization tries to pry into Eugeo.

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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 adviced to use the LN's as your guide. Although, the two games SAO Unleash Blading (Old name: Alicization Rising Steel) 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 Gaurdsmen in Zakkaria. 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 are also some cute Yujikiri moments in their social-mode stories: ("Giving Back" & "An Odd Feeling").

SAO Lycoris also seems a good recommendation for an extensive look on Yujikiri's dynamic: as it shows how the story would go if Eugeo didn't die. It also reveals some small details/funfacts: like how Kirito used to play with Eugeo's face as he slept.

However, even though Lycoris takes everything from the canon Alicization mainline story: it does have a few incorrect facts/changes in the lore/universe: mainly the segments for the girl characters, so not all of it can be taken as canon. But it's still very worth looking into if you want to see the alternate route where Eugeo survives at the final episode for Alicization and watch Yujikiri develop, aswell as seeing how Eugeo gets along with Kirito's girlfriend: Asuna.

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Alicization
Childhood The story starts off with Eugeo and Kirito as children. They are already seem to be the best of friends, making bets with eachother and playing around, tickling 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. The anime often shows Kid Kirito's 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. 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". But then, when their other friend Alice breaks the Taboo Index and gets taken away is when they fall apart. They get seperated---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 eachother 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.

When they see eachother at the Gigas Cedar, many feelings seem to arise. In the anime, they lock eyes with eachother for quite a long 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 sister) that Eugeo stopped smiling until he met Kirito.

(more to be added)

Swordcraft Academy  (Primary Trainee & Elite Disciple) 

They are 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.

(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 eachother really starts to spill. This arc also confronts the topic of love.

(more to be added)

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 selfharm--very likely implied to be due to Eugeo's death. He clings onto Eugeo's sword all the time, even seen sleeping with it. (more to be added)

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.

Moon Cradle

Moon Cradle is an interquel of War of Underworld and Unital Ring. It dives into the 200 yrs 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
Diving back into the Underworld: We get introduced to an Eugeo-doppelganger who calls himself Eolyne. This is where Kirito’s feelings gets very mixed and brings out alot of things out of him. It also traces back to alot of Yujikiri's moments.

(more to be added)

Side Stories
As said before, SAOUB and Lycoris have some event stories that branches out on the canon lore, but there is also Distant Journey: a novel by SAO creator Reki Kawahara that focused on Eugeo and Kirito just after they left Walde farm and before they joined the Zakkaria swords Tournament.

Distant Journey Its given as a bonus to SAO dvd releases.  (more to be added) 

There's also a novel called 32/33 thats also written by the creator Reki, albeit this is more of a fun spin-off rather than a serious part of the lore. In 32/33 novel they graduate from Swordscraft Academy and become Integrity Knights. This is also given as a dvd bonus.

Both of these stories has been translated to read by GSImenas, which you can read on his blog: dreadfuldecoding.blogspot.

SAO Alicization Lycoris
This is basically Alicization Reboot/expansion pack where Eugeo lives from the Cathedral Arc.

it has a special Yujikiri-focused story DLC called Myosotis (also known as Forget-Me-Not). Kirito and Eugeo go on a trip for Kirito to find a 2nd sword for dual wielding. There are many Yujikiri highlights in there to count but notably the exclusive story arc with Dark King Eugeo where they hug tenderly.

 (more to be added) 

SAO Unleash Blading
Mostly a re-telling of Alicization with recaps of the first 2 seasons. There are a few extra exclusive Yujikiri stories though. The main attraction for SAOUB is definitely the homescreen voicelines and their game units.

Eugeo is heavily implied to be talking to Kirito in his homescreen voicelines and vice versa.  (More to be added) 
 * Eugeo has some romantic standard voicelines where he blushes and says "Your eyes are really pretty." & "Can we go somewhere quiet? I want us to be alone..."
 * The night-time voicelines 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.
 * Pajama Eugeo is heavily implied to have been sleeping next to Kirito, and also has alot of very sweet voicelines 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 eachother.
 * 2nd Anniversary Integrity Knight Eugeo has a special partner skill that reflects their swordstance in the anime opening. His voicelines also talk about cooking dinner for Kirito among many other tender lines.

SAO Integral Factor
Mobile game where Eugeo meets Kirito in Aincrad. (more to be added)

SAO Hollow Realization
Eugeo gets summoned to Sword Art: Origin/ Ainground as an integrity knight with no memory. He befriends Kirito. (more to be added)

SAO Fatal Bullet
Eugeo as a GGO player. Somewhat connected to Hollow Realization’s Eugeo but you don’t need to know anything from it to get into it. (more to be added)

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.)

(more to be added)

MISC. games

 * SAO Arcade
 * SAO vs Accel world
 * Crossing Void
 * Shironeko x SAO (Collaboration)

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 monlogue in his head that says describes an "emotion he cant even name"--that describes it to be painful, yet wisful 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 indescrible 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 eachother. 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 seperated 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 aswell as noting Kirito’s boyish/mischievous smile.
 * When Eugeo finally reunites with Kirito in the Cathedral after getting seperated--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.
 * In the prologue of Myosotis, 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. 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.
 * 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 aswell. 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 eachother 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, aswell 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 mightve swept me off my feet" - Fatal Bullet Eugeo

 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 seperated in the Cathedral during the aftermath of the fight with Alice, they both thought of eachother 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

'''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''

“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'''"Something powerful welled up in my chest, and I had to fight it down to maintain control." -' Kirito, 'SAO Light novel vol.9: Alicization Beginnings, - localized by YenPress''

"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

"Love is not something you seek, it's something you give."

 (more to be added) 

Symbolism & Subtleties
Kirito and Eugeo intentionally or not are regarded as queercoded, specifically bisexual. There 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.

The other is 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.

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 Japanese 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. And 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, aswell 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, aswell 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 and also in this particular groom-like 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.

'' (more to be added) ''

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. His first debut has to be around the Light Novel volumes 23 and 24. They meet eachother 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 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's favorite: Honey pies. Kirito really gets the urge to jump over the table and strip him, but feels like he's being held back by Eolyne's aura. In here, they have a little chat and Eolyne 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 he'd just met Kirito.

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, aswell 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)

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 eachother
 * 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)

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

(more to be added)

Fanservice
Several of the games allow Eugeo as a romanceable partner of which you can date, touch, kiss, and even sleep in a bed with. Eugeo is the only male character that continuously gets bed scenes with Kirito; paired together with a special 2D-drawn CG. They proceed to hold hands and act like lovers while Eugeo is half dressed. You can also bridal carry him in these games. 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.

Other character interactions across the novel, several games, and official content poke fun or suggest that Eugeo and Kirito are more than friends. 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.

(also the special voiced cutscene where primary trainee Kirito takes his shirt off. add later.)

SAO Hollow Realization is even less shy about making them intimate, and is perhaps the boldest of all games so far. The dating-sim scenes and interactive functions/options are unparalleled and are straightup 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 voicelines becomes highly sexual.


 * When Bridal carrying him you'll bashfully hear him saying "omoku nai?" (Am i not heavy?) if set on the bed he'll say "kinjo suru yo" (im 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...".
 * 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.
 * Theres a date scene where Eugeo tucks his hands under Kirito's clothes and blushes at how warm his skin is.
 * A more implied 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. 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.

In SAO Alicization Lycoris, Kirito makes quite forward/questionable teases with Eugeo: such as deepening his voice & letting lowchuckles while calling him Eugeo-kun--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.

There's also the Myosotis DLC where we could've had the chance to see a hotsprings 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.

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 bedscenes in this game too and 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.

(to be added: Groom Eugeo fig with yujikiri quotes, wedding rings with crunchyroll saying: "share eugeo and kirito's love")

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 truly is saying something.

He's also made a 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." It's a lighthearted story where their school bullies Raios & Humbert have been bitten a poisonous crab and 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 enemies talk to eachother over tea and their peace offering: cake. 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. 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.

There's also fan-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], The voice cast and creators also joke a lot about Eugeo being the heroine of SAO throughout special video/radio broadcasts. (this joke has seeped it's way into sao integral factor april fools)

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 "Eugeo, yes."

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.

Shironeko did a SAO collab and has dedicated an entire seperate event for Yujikiri called "My Dear Best Friend"

 (more to be added) 

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.

Trivia

 * 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.
 * They held hands in bed. twice. in Lycoris and Hollow Realization bedscenes. Theyre also both from the final/last bedscenes.
 * 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. (Founded by Souseki Natsume, more info here), 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..."
 * Its quite likely that the creators intended for Kirito to be bi, with Eugeo being his true bi awakening. His dual wielding is already symbolic for bisexuality: with it being "swinging both ways" and also a japanese slang, 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.
 * 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, aswell 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.
 * Novel and anime adaptations depict Eugeo being of a very similar and notably important place to Kirito as his IRL girlfriend, but in the games it gets taken a step further. Eugeo is the only male character to get consistent lovers-like dating sim segments + bedscenes and handdrawn cgs for it, paired together with special voicelines like "I'm getting nervous..." "Don't look this way...!" "Let's do this again.../do me another favor."
 * They hold hands often in the anime, and often passionately. This gets referenced later in Unital Ring, when Kirito holds Eolyne's hand in LN 26.
 * They both seem to be in love with eachothers 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 aswell, saying how it reminds him of the night sky and that the color suits him.
 * 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).
 * 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.
 * 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 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.Main-qimg-2266e6106d7fdaf3c799efc1171fe666.png
 * 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.
 * 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.


 * Whenever Eugeo gets fatally wounded--he somehow always seems to look at Kirito with a warm, peaceful smile.
 * Eugeo is regarded as Kirito’s best sleeping partner in a mobile game event story. (Memory Defrag)
 * 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.




 * Kirito and Eugeo share ring merchandise depicting their two swords connected with a caption that they love each other and 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 and about Kirito, such as: Our memories are right here, Love is like watering flowers, Lets go no matter where it takes us/together till the end.

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