"There are so many capable men... and all they can think to do is rob a convenience store? Kinda weird... you'd think a group this big might just, y'know... have bigger goals than that... You're all sick. And you need a cure."

Kai Chisaki to Team Reservoir Dogs in "Unleashed"

Kai Chisaki (治崎 (ちさき) (かい) Chisaki Kai?),[1] also known as the villain Overhaul (オーバーホール Ōbāhōru?), is the Yakuza Captain of the Shie Hassaikai.[2] He serves as the main antagonist of the Internship Arc.


Kai Chisaki is a young Japanese man with short brown hair and small golden eyes. His has three piercings in his ear and his face is always obscured by a mask that he wears over his mouth and nose.

Chisaki appears to be a classy Yakuza gangster who often dons a black suit and tie with white shoes and a brown belt. Overhaul sports a green jacket with sleeves that end at the forearm and a collar decorated with a lot of purple furs. Overhaul's most distinctive features are his white plastic gloves and his signature orange plague doctor mask.


After fusing with Shin Nemoto, Kai gets an additional two arms deformed with spiked claws and black parts of Shin's cape. His hair gets spikier, and his mask rips apart. It seems to be fused onto his face which is also covered in black fabric. Shin is presumably conscious in the fused form as his mouth is used through Chisaki's right hand and his Quirk is able to be in use.[3]

After fusing with Rikiya Katsukame, Kai's lower body is fused into a monstrous stone structure, protruding multiple appendages each equipped with clawed hands. Kai's upper body is the same but lies within the mouth of the structure. The upper jaw has Rikiya's mask.[4]


Overhaul kills Eri's minder

Overhaul disposing of one of his expendable pawns.

Kai Chisaki is a mysophobic, antisocial sociopath obsessed with returning to the world to the way it was before the Quirk phenomenon. Due to a combination of an old theory claiming Quirks derived from rats and his own mysophobia, Chisaki believes that Quirks are actually a plague on humanity. He believes the Quirk epidemic has changed the world and infected society with "Hero Syndrome". Chisaki is extremely determined to eradicate Quirks from the world in order to return it to its former state with the Yakuza in power.

Chisaki is very germaphobic and hates anything he feels is dirty. He likes to avoid dirty places and hates when people dirty him or the area around him. Chisaki will even break out into hives when covered in dirt or blood. He views Quirks as a sickness and treats them as he would any other kind of filth.

Overhaul's cruelty

Overhaul's lack of humanity

Chisaki feels as if he owes a debt to the Boss and the Yakuza for taking him in. Even from a young age, Chisaki was dead set on returning that debt no matter the cost. The Boss would try to sway Chisaki to a more honorable path to no avail. He would get in violent fights and eventually involved himself in illegal dealings.

Chisaki grew up and became a villain determined to reinstate the Yakuza even if it meant taking advantage and abusing others. Overhaul has no remorse for those he uses or kills for his ambitions. He looks at everyone as expendable pawns for his ultimate goal. In order to achieve his ambitions, Overhaul went as far to force the Boss into a comatose state to use his grand-daughter to create Quirk-Destroying Bullets.

Overhaul has no moral compass and has an enormous ego. He views himself as the only person in the world that's enlighted to the Quirk epidemic. Overhaul believes that he is always right and all others are wrong to oppose his conquest. Overhaul also believes he should be the to inherit All For One's place as the king of evil.

Overhaul doesn’t value humans and views people as pawns for their utilitarian value. He carries this sentiment even towards the people in his organization he’s known since childhood; Overhaul treats them all as dispensable. He considers everybody, even childhood friends and his closest right-hand man, expendable and his subordinates are made to wear masks like him so he doesn't have to breathe the same air.

The only person Chisaki has ever shown concern for is the Boss who raised him. Despite his feelings for the Boss, Chisaki incapacitated him to achieve his goals. Chisaki abused the Boss's young granddaughter without remorse to create a drug that could destroy Quirks.

Kai Chisaki remembers his debt

Chisaki's fierce determination to revive the Yakuza and repay his debt.

As a leader of his organization, Overhaul is levelheaded and possesses a strategic mindset. According to a conversation with Twice, Overhaul seems to be nice at first. Whether he is acting or behaving genuinely, Overhaul does possess polite mannerisms and can come off as very calm and classy. This is evident from his meeting with Mirio and Izuku. He will speak to others in a very composed manner and display very good social skills in the required situation. When aggravated, Overhaul shows his killer instincts and lashes out violently.

Overhaul's failure to recognize others, and his own obstinate nature, brings about his end. Despite his strong-willed attitude, he is capable of expressing true fear and shock, as he was horrified when the League of Villains took his quirk drug, his arms, and taunted him for his lack of power. His facial expression was that of fear, as he was now ironically being the very thing he had wanted to inflict on others.


Overall Abilities: Overhaul is a super powerful villain that gained the attention of All For One. He is very intelligent and extremely dangerous due to his Quirk and lack of remorse. He was able to overpower Rappa, Sir Nightye, and Izuku as well as put up a fight against Mirio Togata, a U.A. student worthy of the No. 1 Hero spot.

Enhanced Agility: Chisaki was challenged by Rappa five times, and each time Rappa lost despite his speed and strength. This implies that Chisaki has high speed and reaction time of his own to be able to accomplish this as his Quirk requires him to touch his opponent for it to take effect. Chisaki's fast reaction time is also shown when he was able to evade Mirio Togata's punch, albeit he was left with a scratch on his face.

Overhaul Disassemble

Overhaul activated.

Enhanced Durability: Chisaki has great durability as he was assaulted by several of Mirio Togata's punches and was able to take them as well as remain fully conscious despite still receiving bad injuries, whereas a simple attack from Mirio was enough to knock out and badly injure two of the Eight Expendables to the point where they could no longer fight. Later on, he was able to survive punches from Deku who was wielding One For All at a 100%. Chisaki showed little reaction to having both of his arms destroyed by the League of Villains.


Overhaul (オーバーホール Ōbāhōru?): Chisaki's Quirk grants him the ability to disassemble and reassemble anything he touches, effectively giving him full control over matter. Overhaul can disassemble people to kill them or reassemble them to heal their wounds. He can also do this to himself and even merge his body with others.

In battle, Overhaul can freely manipulate his surroundings. He can move the ground to maneuver himself to reshape the area into some advantageous for him and harmful for his opponents. By touching his targets, he can completely blow their body apart whether it be a limb or the entirety of it.

Battles & Events

Internship Arc


  • Overhaul's characters in his name are composed of "治" (chi, lit. "govern, regulate, administer"), "崎" (saki, lit. "promontory, cape, spit") and "廻" (kai, lit. "revolve, return, curving").
    • "廻" (kai) notes his quirk “Overhaul” that can disassemble and reassemble anything that he touches.
      • “chi” (治) in his surname has different meanings attached,
      • It could mean (to treat, to cure disease) how he believes everyone is sick, obsessed with finding a cure.
      • (to research, to specialize in a topic) noting his research on destroying quirks.
      • (to punish, to discipline, to teach someone a lesson) referring to how Overhaul treats Eri as a subject for his bullets and force her to obey through intimidation and how he was hoping to use the quirk destroying drugs to control society through fear.
      • (to exterminate, to kill) seen several times that he used his quirk to kill others.
  • Overhaul and Tomura Shigaraki have several similarities:
    • Both wear plain clothes and a coat but also have unique masks.
    • Both their masks have some connection to their character:
      • Tomura's hand has some connection to his father.
      • Overhaul's plague-doctor mask parallels his mysophobia.
    • Both are succeeding leaders in their organization after a previous leader was toppled.
    • Both their Quirks have similar attributes:
      • Both require direct contact with their hands to touch their target for their quirks to work.
        • However, unlike Tomura who needs all five fingers to activate his quirk, Overhaul appeared to only need a finger at the minimum to use his quirk.
        • Also, Tomura's Quirk can disintegrate anything while Overhaul's Quirk can disassemble anything (thus destroying them) as well as reassemble them.
      • Both Quirks are destructive in nature to their enemy.
        • However, Overhaul's Quirk is able to reassemble objects while Tomura's doesn't.
  • Overhaul's first encounter with the League of Villains bares similarity to Stain's first encounter with the league.
    • Both were committing their own acts of violence before being approached by a member of the league.
    • Both had some level of interest in the league before revoking their interest after realizing the league's limits, which led to a conflict between them.
    • Both ended their meetings in bad taste with the league.
    • Both stated that the league had some form of potential and would see how that grows. Though for Overhaul, that potential is more for his own motives.


  • (To Team Reservoir Dogs) "You guys have an illness. Illnesses must be cured."[5]
  • (To Izuku Midoriya) "When someone lays a finger on me, I can't help but feel the need to cleanse myself."[6]
  • "To reach an objective, you need a plan."
  • (To Eri) "You were born to destroy people."[7]
  • (To Eri) "Each and every one of your actions kill people. Yours is a cursed existence."[8]


  1. My Hero Academia Manga: Chapter 151 (p. 15).
  2. My Hero Academia Manga: Chapter 125 (p. 3).
  3. My Hero Academia Manga: Chapter 153.
  4. My Hero Academia Manga: Chapter 157.
  5. My Hero Academia Manga: Chapter 115.
  6. My Hero Academia Manga: Chapter 154.
  7. My Hero Academia Manga: Chapter 151.
  8. My Hero Academia Manga: Chapter 151.

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