Kirigaya Kazuto/Relationships

Asuna
Asuna is Kirito's partner and main love interest in the series. Among all the people Kirito met, she is the closest and dearest to him. Originally the two of them only think of clearing the game, but their relationship begins when they partied in the 1st floor. During the boss fight in the 1st floor, he called Asuna by her name for the first time (due to noticing her character name below the HP gauge). She is also one of the two people knowing the reason why Kirito became a Beater (the other was Agil). When the two of them partied again in the 74th floor, Asuna normally cooks for Kirito. As the series progresses, the two of them fall in love with each other. After the two of them declared their love for each other, they were so attached to each other and only concern of their safety.

Their relationship is very serious to the point that they cannot live on if one of them dies. An example is shown when Kirito asks Asuna not to take part in the boss fight in the 75th floor to which she replies if he did not return, she will commit suicide thus joining him in the fight saying she will protect him Kirito fights with the final boss on the 75th floor, and is about to die, when Asuna jumps in and saves him, at the cost of here life(in-game). This also led to the two characters getting married in-game where they resided in the 22nd floor for two weeks as their honeymoon until being called back to the frontlines.

Kirito also does not give concern to his safety when it comes to rescuing Asuna like when he tries to fly up the World Tree uncaring whether he falls and his avatar dies or not. After rescuing Asuna in ALO, the two of them finally meet face to face and they officially became a couple in the real world. Kirito tends to take things on to himself when it concerns Asuna as shown in the GGO incident where he didn't tell Asuna that he could very well die (due to the theories they held about the incident at the time) and took part in the mission in secret since he didn't want to risk her safety. Asuna eventually finds out the details on her own and rushes to Kirito's side, holding his hand as he is fighting in GGO. Kirito said that it was her warmth that gave him the strength to win.

During Volume 10, after Kirito's was sent to hospital due to an encounter of a former Laughing Coffin member and was subsequently kidnapped, she along with Yui went to great lengths to find him and is currently waiting for Kirito to regain consciousness.

Klein
Klein is Kirito's first friend before meeting Asuna. He became Kirito's friend after he asked Kirito to teach him to play SAO. Klein was one of the few people that Kirito considered as a "friend". Klein really cares for his friends and dedication to keep them all alive, which Kirito greatly respects. Klein tends to worry about Kirito, since he knows his loner nature, and tells Asuna to "take care of him" and that he "isn't a bad guy" to which she replies she will and she has long since known respectively.

Klein is also responsible for giving Kirito extra strength when he broke down after learning he couldn't revive the dead (Sachi). He regularly meets with Kirito and his friends and occasionally go with them in quests in ALO, especially after the release of the World Seed. One such instance includes the quest for Excalibur.

Agil
Agil is an axe wielding merchant who has a good relationship with Kirito. He is one of the two people who knows the reason why Kirito became a Beater (the other being Asuna). Like Klein and Asuna, he also respects Kirito, and is always offering any help he can when Kirito needs it (like sheltering him when Kirito became famous after his Dual Blades becomes known, or implementing the "Seed" that Kayaba gave Kirito). Outside of SAO he is married and the owner of the Dicey Cafe where Kirito and his friends often meet up.

Silica
Silica is a player that Kirito met when he was wandering around in the 35th floor. When Silica asked him why is he being kind to her, he gave her a "manga-like" answer that she resembles his "sister". As they journey together, Silica begins to develop feelings for Kirito. After reviving Pina, she realizes that she can't follow Kirito to the Frontlines due to her lower level tho she still is happy to be able to meet him and they keep in touch by adding each other as friends, something Asuna later noted as rare due to Kirito being a anti social solo.

After the ALO incident she goes to school with Kirito, Asuna and Lisbeth. Both Silica and Lisbeth are in agreement to give both Kirito and Asuna space for one month before they make their individual moves on him. Though after seeing how close Asuna has gotten to Kirito (made him lunch at the time) they quickly regret their "pact".

Lisbeth
Lisbeth is a close friend of Asuna who recommended her to Kirito. He accompanied her in the quest for the special ore required for the job. During the quest, she also develops feelings for Kirito without him noticing. After the quest, she becomes Kirito's personal blacksmith. She is devastated when she finds out that Kirito is Asuna's crush. But finds solace when Kirito tells her about the "Black Cats" and that for the first time after losing his guild he had felt natural while partying with her.

Despite initially giving Kirito to Asuna when the game is cleared she knows right away that Kirito is the one who did it and among all the cheers she shouts out at the top of her lungs that she loves Kirito and that she swears they will meet up in the Real world. Right after they meet in the real world, she becomes a regular player in ALO and frequently takes on quests with Kirito and his friends and takes up tasks of upgrading their equipment. She also goes to school with Kirito, Asuna and Silica.

Sachi
Sachi is a member of the guild Black Cats of the Full Moon who Kirito befriended. They became very close to the point of sleeping together in the same room; their relationship described as "two stray cats licking each others' wounds" as they comforted each other. Their relationship was close enough that they had a shared page in each others' inventory (similar, but not quite at the level of married players who had combined inventories). Kirito promised her that she would not die, though unfortunately, he would not be able to keep his word. Even after her last message gave him the strength to live, he still never fully was able to escape his guilt until he married Asuna.

Yui
Yui is Kirito and Asuna's in-game daughter who is an «AI». While Kirito loves Asuna as his fiancé/wife, Kirito loves Yui as his own daughter and Yui in turn thinks of Kirito and Asuna as her parents. In the real world, Kirito uses his skills and resources to make a device for Yui to view the real world even whilst she is in virtual reality and gives her the ability to communicate with them.

Yui is probably Kirito's second most beloved person while Asuna is the first. In ALO she takes the form of a navigation fairy who is always seen on either Kirito or Asuna's shoulder. Yui tends to misunderstand why humans aren't direct in expressing their feelings saying if she was the one who did it then she would simply be forward about it (she then kisses Kirito). She also gets annoyed when any girl other than Asuna or Lyfa interact with her "Papa".

Kirigaya Suguha / Lyfa
Kirigaya Suguha is Kirito's real life stepsister/cousin. Kirito created distance between them when he found out they weren't real siblings but instead cousins. After clearing SAO this becomes something he regrets as he tries to reforge their relationship. When Kirito was trapped in SAO Suguha was conflicted with her feelings for Kirito and eventually realized she loved him. she originally joined ALO as using the alter-ego name Lyfa in an attempt to better understand him. She becomes depressed when Kirito visits Asuna on a consistent basis realizing where his feelings lie.

She unknowingly met Kazuto under his screen-name Kirito while he was trying to save Asuna in the world tree. She eventually developed feelings for him without knowing Kirito was really Kazuto and was distraught when she found out who he was. She has recently come to accept her emotions and feelings and accompanies Kirito and his friends in their adventures. Aside from Asuna, she is the only one Yui is ok with when it comes to Kirito, considering any other girl who interacts with her "Papa" as cheating.

Sinon
Sinon is Kirito's partner in GGO. When they first met, they got along but that all changed when she learnt of Kirito's real gender (due to Kirito's avatar in GGO heavily resembling a girl). The two swore to each other to survive in the game so they can settle the score but they soon worked together after learning Death Gun's existence in the game. When they were hiding from Death Gun, the two of them shared their deep dark secrets which is the same sin they committed and that is they "kill someone" before in their lives (Sinon shot a criminal when she was 11 while Kirito killed three members of Laughing Coffin in SAO).

After knowing Death Gun's is actually two people and their next target is Sinon, Kirito comforted Sinon and decided to protect her. She develops feelings for Kirito afterwards. After they defeat Death Gun in the game, the two of them revealed each other their true identities and their addresses. After the Death Gun incident, Sinon joins ALO on Asuna and Lisbeth's recommendation as a Caith Sith archer. After Sinon obtained the Excaliber, she handed it over to Kirito under the condition that he always think about her when he uses the sword.

Eugeo
Eugeo is Kirito's best friend. Kirito and Eugeo shared the same «Sacred Task» of cutting the «Gigas Cedar». They embark on a quest to go to the Mountain Range, where an unfortunate mishaps occur. Six years later, Kirito once again meet up with Eugeo, where they once again team up to go find their long-lost friend, Alice.

Alice
Alice is one of Kirito's friends when Eugeo and Kirito were 11 years old. Later, after a accidental mishap during a quest to find ice, Alice was taken away from her village to be tried and executed. However, seven years later, she appeared in a ghost-like form and tells Kirito that she is waiting for him.

Nurse Aki
Nurse Aki is a nurse who Kirito was acquainted with. She took care of Kirito previously during his long rehabilitation. She watched over Kirito when he was going to investigate the Death Gun incident. Outside his friends from SAO, she learned about Kirito's dark secret, "the fact that he killed three players from SAO". After that, she encouraged Kirito that he have the right to redeem himself by thinking of those people Kirito saved. She appears to have respect for Kiritos maturity in handling his guilt and as he enters GGO calls him a "Hero".

Kikuoka Seijirou
Kikuoka Seijurou is an investigator in the «SAO Case Victims Rescue Force» who Kirito was acquainted with. He has taken a personal interest in Kirito's abilities thus uses the GGO incident to forge a relationship with him, Kirito does not trust him at all since he never reveals the full truth but still feels grateful to him since he was the first one by Kirito when he woke up from SAO and was also the one who told him where Asuna and the others were located.