Ajin Wiki
Name Kaito
Kanji 海斗
Rōmaji Kaito
Age 17
Gender Male
Hair Color Blonde (Dyed)

Black (Natural)

Eye Color Yellow
Occupations Convict (Chapter 28 onwards)

Student (former)

Height 166cm (current)

132cm (child)

Voice Actor Yoshimasa Hosoya (Japanese)
Bryce Papenbrook (English)
First Appearance Chapter 1 (Manga)
Ajin Part 1: Shōdō (Film)
Episode 1 (TV Anime)
Image Gallery

Kaito (海斗) is Kei's childhood friend and helped Kei escape from the authorities when he first discovered he was an Ajin.


Kaito's hair and eye color.

Kaito is a young man with an average build. He sports a black and blonde undercut with his hair spiked up. His eyes are the same golden color of his hair beneath thick, heavy eyebrows.  
Like most characters, Kaito's apparel changes throughout the series, but is most often seen in a black button-down shirt with a smiley face motif, capris, and hiking boots. He also wears a distinctive, single smiley face earring on his left ear. The smiley face motif is something that appears on all his clothing throughout his life.
When he is admitted to jail, he wears a convict's jumpsuit and his hair is drawn shorter.


Kaito is a pure altruist, seemingly beyond his own control. He is shown to be a very loyal and supportive friend towards Kei, but as Kei notes, Kaito would help anybody in trouble no matter who they were because it is just his inbuilt nature. This is demonstrated in chapter 28 when he insists on helping Kotobuki and in chapter 69 through multiple events in his childhood. He helps people without hesitation, no matter what the consequences may be -- even if he is severely beaten or arrested. It is very likely that he has savior complex.
While helping Kei, though situations become increasingly worse, he appears to retain a very positive, determined attitude. He is very resourceful and though he is not as intelligent as Kei, he is able to make tactical decisions while they were on the run together.
After being locked in jail, his demeanor becomes more cautious; however, he is still considerate of others. In spite of Kei abandoning him, he is still willing to do anything to ensure his safety, although he does respect Kei's wishes to be left alone if need be.
He appears for the most part carefree except for one moment in his childhood when he cried because Kei had canceled his plans with him. However, this is the earliest scene of Kaito's childhood we are shown, and he does not express feelings of sadness of pain ever again, no matter the situation. The only other time he was shown to in some way "break character" was a flashback scene in chapter 69 when he and Kei were hiding out in the abandoned cabin, and he remarked "What a pain" all of it was, an interesting insight into his personality. He is therefore - although undoubtedly selfless and altruistic - not immune to feeling the weight of all the favours he does for other people, nor does he necessarily do them because of personal feelings. In his reunion with Kei, he states that he "always hates just how much of an idiot he is".
Though very different to Kei in many ways, he is still similarly quite reserved about himself. There is still much about the nature of his personality left to be explored.


Although they didn’t attend the same elementary school, Kaito used to be good friends with Kei when they were very little, and would play together often. However, when Kei’s mother suddenly told her son to stop being his friend because he was the son of a convict, Kei cut him off immediately and very easily, which initially hurt Kaito a lot. When Kotobuki inquired about his friendship with Kei in chapter 69, he simply replied that he “didn’t remember much of it”.

Kaito seemed to live a life where he would constantly help people who would never return the favour. Kei appeared to be the first time he experienced it, but he grew accustomed to this kind of treatment from people throughout his childhood. When he stood up to a bully for another classmate in elementary school, the classmate didn’t even do as much as to admit to their teacher that Kaito was not the one to start the fight, instead he passively claimed that he did not know. Despite this, Kaito invited the classmate to walk home together with him, and this became a repeating pattern through his life that moulded the core of his character -- he would be good to people, they would not repay his kindness, but he would help them again. 

A few years after that event, Kaito was shown smoking and drinking alcohol, seemingly having fallen into the wrong crowd. Some older friends asked him if he wanted to join them in stealing bikes and he followed, but they were caught by the owners of the bike and had to run. When his friend said that he had forgotten his wallet that had his ID in it, Kaito ran back to retrieve it, taking a very harsh beating, but dropping the wallet down a drain. The friend messaged him some time later asking if he wanted to join him for karaoke, with no mention of a thank you for what Kaito did for him the other day, but Kaito accepted his invitation regardless.

Kaito and Kei did not attend the same high school. Kaito is known to often go for rides on his motorbike, and appears to know lots of people.


Early manga

Kaito helps Kei escape

Kaito is introduced very early in the manga. He waves to Kei as he sees him passing by, but Kei ignores him, denies knowing who he is to his friends, and calls him a "weirdo". Kaito appears unphased.

When Kei is revealed to be an Ajin shortly after the truck crash, Kaito immediately begins preparing to help him. After receiving a call from Kei to meet where they caught a rhinoceros beetle as children, Kaito fends off a police officer about to capture Kei and they escape together on Kaito's motorbike. Kaito expressly states that he does not care that Kei is an Ajin and is mildly interested to find out that there are other Ajin out there.

After fighting off two thugs who attempted to capture Kei for money, Kaito also discovers that he is not as acutely affected by Kei's Ajin scream. Following another attempt at capture by another motorcyclist, Kaito tells Kei that he believes that he is human and that he is going to help Kei no matter what. After Kei repairs his broken legs by killing himself and they are about to flee on the motorcyclist's bike, Kaito's expression changes to one of concern. They reach an abandoned cabin and decide to rest there. Kaito goes out to buy some clothes and supplies and returns after a while.

Kaito voices his inner feelings.

After returning from the shops, Kaito then sits down and thinks about the details of how exactly he and Kei will escape to Kyushu. While figuring things out and getting lost in his thoughts, he remembers the comparably minor plans he had made with his other friends and feels bad that he is unable to fulfill them -- but he needs to do something about Kei's situation because "he'd be hopeless on his own." Feeling the weight of all his commitments to different people, he says (in a manner quite surprising for his character) "What a pain, all of it." While not made clear, he is likely referring to the never ending cycle of favours he has done for people all his life. After this, he goes to sleep.

He suddenly shoots awake and wonders how long he was asleep, as they were supposed to take turns sleeping and keeping watch. He then finds that Kei isn't there, and has left a note where he explains how he shouldn't have dragged Kaito into his problems and that he will find a way to make it on his own. Kaito appears amused and remarks that Kei has more guts than he'd thought.

Kaito is then seen walking along a back road alone.

Kaito still wishes to help Kei.

In chapter 28 it revealed that Kaito was arrested and sent to juvenile prison for assisting Kei's escape. When his new inmate, Kotobuki Takeshi, is being harassed by the other inmates for information on how he escaped the prison, Kaito intervenes and tells them to knock it off. Kotobuki then tells Kaito that he needs to shut his mouth. However, when the same thing happens later in the bathrooms and the inmates become physical, Kaito intervenes again. Kotobuki still shows no gratitude and when the inmates turn to fight Kaito, he says that the fight will be 3 on 1 and to leave him out of it. Kotobuki approaches Kaito later and tells him that favours do not get repaid in the real world (something Kaito already knows quite well without being told) and that if he continues to stick up for him all he will receive is an extended sentence and some permanent injuries. Despite all the warnings Kotobuki gave, later that night Kaito once again helps Kotobuki when he is being beaten, causing Kotobuki to call him a "supreme idiot", but he helps Kaito by taking out the others with his IBM.

Later, Kotobuki approaches Kaito and shares his cigarettes with him. He asks him what Nagai Kei is like to which Kaito replies is his first friend, adding that if he tells him to back off he will, but if he is ever in trouble he will definitely go save him. Kotobuki then repays Kaito’s acts of kindness by telling him that he will let him escape from prison one time if he needs to help Kei.

Iruma Base arc

Kaito is shown briefly in chapter 59 to be watching Kei on the Iruma Base runway on TV in prison. In chapter 64, he escapes the prison with the help of Kotobuki's IBM, who launches him into the air and carries him through the sky outside the walls and towards Iruma Base. Chapter 69 is a flashback chapter that explores Kaito's childhood, the start of the chapter shows Kaito and Kotobuki having another conversation about Kei.

Kaito during his reunion with Kei.

While Sato is saying goodbye to Kei, Kaito makes a very surprising entrance on a motorbike, a distraction which allows Kei to hit Sato with a tranquilizer dart. Sato detonates the explosives strapped to him before he becomes immobilised, causing an explosion, but Kaito is unharmed. He then reunites with Kei, who asks him with an exhausted expression why he decided to come to a place so dangerous and reminds him of the note he had written telling him to stay away. Kaito's expression and tone through the scene is one that is slightly amused. He admits to Kei that he realises it is definitely a dangerous place to be -- and that he "hates how much of an idiot he is". Their conversation does not last long as Sato appears behind them and shoots a bullet through the back of Kaito's neck and through Kei's eye to his brain. When Kei is revived, he notices that Kaito's bulletwood has healed, but he has not regained consciousness. He drags him underground to give him CPR in hopes of reviving him, and after some time, Kaito's gentle pulse and breathing is restored.


Kei Nagai

Kaito used to be childhood friends with Kei prior to Kei abandoning him after finding out Kaito was the son of a convict. Kaito appeared very hurt when Kei abandoned him, shedding tears despite his carefree, cheerful attitude. However, until present day, it appears that Kaito still cares for Kei's safety as during their time as fugitives, he put his life on the line to protect him. It is later revealed that Kaito is simply an altruist, and helps all people who are in trouble no matter the consequences. It is not to dismiss that Kaito may have a closer friendship with Kei, but he does tell Kotobuki, in regards to their childhood friendship, that he "doesn't remember much of it". While they were on the run together, Kaito did a lot for Kei -- not just helping him escape and physically defending him, but verbally calming him down and cheering him up too. Although, despite this, he is later shown to mutter to himself "what a pain" all of it is, and adds that he has no choice but to help Kei because "he'd be hopeless on his own". This suggests that up till that point, Kaito was not helping Kei for any special personal reason but just because it was his nature to help people. However, after Kei "abandons" him and leaves a note that expresses his care for Kaito's wellbeing and safety, Kaito appears impressed by Kei's guts. After this, he seems more enthusiastic to go to Kei's aid again, possibly because he now sees a true friend in Kei, as one who repays his kindness and actually cares about him. During their reunion, Kaito seems happy to see Kei, and appears far more genuine when he speaks to him, even subtly opening up about himself, as opposed to the way he behaved towards Kei in the early manga.

Takeshi Kotobuki

Kaito meets Takeshi in jail when the other inmates beat up Takeshi for information on how he manages to flee prison without being caught. Kaito stands up for Takeshi as dislikes unnecessary fights. After Kaito risks becoming the target of their severe beatings, Takeshi use his Black Ghost to help Kaito fend them off. It appears that Takeshi thinks Kaito is a supreme idiot, but respects his wishes to save his friend as a favor. Kaito's need to help Takeshi is probably due to his loyal nature. Afterwards, Takeshi offers Kaito help to get out of jail, should Kei get into any trouble.

Abilities and Powers

As far as has been revealed, Kaito does not appear to be an Ajin. However, Kaito is shown to have excellent combat ability, saving Kei numerous times with willpower and skill alone. He is good at close-range combat and was also seen doing a mid-air kick, which resulted in him kicking his opponents in the head, efficiently knocking them out. Kaito seems to have been brought back to life by Kei's flood after he was shot by Sato, but whether he is now an Ajin is unknown.


  • "I don't like it. The sun. It's so selfish...always acting all high and mighty and looking down on us." (chapter 3)
  • "You're human. At least that's what I think. So if you're going some place where you don't know anyone but me...then you are just a human." (to Kei, chapter 3)
  • "If he says he doesn't need me, I'll back off. But if something ever happens to him, I swear I'm going to go save him." (to Kotobuki, about Kei, chapter 28)
  • " "Children are innocent and cute." Some people say that, right? Do you think those people believe they used to be cute and innocent, too?" (to Kotobuki, chapter 69)
  • "Yeah. I know right? I always hate...just how much of an idiot I am." (to Kei, chapter 72)


  • In chapter 28, Kaito's smiley face earring was drawn frowning. It is drawn smiling again when he has escaped prison in chapter 71.
  • His name consists of the kanji for sea (海) and 斗, which refers to the constellation Ursa Major. It is interesting to note that in Chinese, the hanzi 斗 (read as dòu) means "fight."