Shie Hassaikai Boss

Age shows on him: a heavily lined face and hair gone gray. Through his years in charge he dressed in kuro montsuki, the most formal thing a Japanese man can wear, a black haori over dark gray hakama with white tabi and sandals, and the choice stated plainly which set of values he stood on. The coma took the rest of him. Roused after the Final War, he is gaunt to the point of frailty and gets around in a wheelchair.

For a man running a criminal organization he was unusually rigid about right and wrong. As heroes hollowed out the yakuza's influence he still refused every cruel or criminal shortcut back to relevance, holding that a code of chivalry was the only thing separating his people from villains, and he came to accept with some grace that the Hassaikai were near their end.

The same man took an orphan off the street and raised him as a son. When Kai brutalized people in the group's name he thanked the boy for trying to defend their honor before telling him he had gone too far, and he kept trying to steer him even as drugs and black market work pulled him further out. He did the same for Eri after her own mother disowned her. What he would not do was consent. Shown a plan that ran on experimenting on a small child, he asked Kai whether any humanity was left in him and told him to leave if he could not follow the path laid out for him. Kai answered by putting him to sleep. Woken years later, he refused the title Kai still used on him, said the Hassaikai was finished, and made clear that the apologies Kai owed belonged to Eri, promising to hold him to account for the rest of his life.

The Hassaikai were an old fixture of Japan's underworld, and the Boss led them through the era in which the arrival of heroes gutted the yakuza for good. Once All Might became the Symbol of Peace, his people were reduced to hired muscle, scraping by and openly called an endangered species. He found Kai Chisaki as an orphan boy in the streets and raised him in the trade. Kai repaid him with loyalty and violence in equal measure, brawling with rival gangs, opening a drug business the Boss had explicitly forbidden, and insisting that obsolete ideals would never save the organization; the Boss, for his part, understood that all of it was meant as thanks and told him anyway that he had stepped over the line.

His daughter turned up one day with a toddler she had decided was cursed. Eri's Quirk had erased her husband from existence, and the power resembled nothing on either side of the family, the product of a rare mutation. Since Kai's own Quirk worked on similar principles, the Boss put Eri in his care and asked him to find out what she could do. The research ran through mice, surgeries and blood samples, and the answer, Rewind, frightened even Kai. It also gave him a plan: seed the black market with an incomplete Quirk-destroying drug, sell the finished version high once villains wanted it, then sell heroes the antidote, with Eri sitting at the center of both markets. The Boss refused to consider it. Kai used Overhaul on him and left him comatose, meaning to wake him once the Hassaikai stood again.

Kai still visited the bed and still believed the whole enterprise was for the old man's sake, apologizing there in advance for the noise the coming raid would make. The raid ended the group. Every member was arrested, Eri went free, and the police found the Boss lying just as Kai had left him. Then the League of Villains ambushed Kai's prison transport, took the remaining drugs and destroyed his arms, and with them any chance of ever reversing the coma; he screamed as the last of it came apart around him. Eri, with no relative left able to take her, was raised by U.A.'s staff, and it was weeks before she smiled once and far longer before she could live like an ordinary child.

Kai's fixation outlasted his power. After All For One's prison break emptied Tartarus he wandered rattled and Quirkless, repeating the word Boss, and traded Lady Nagant an identification of Izuku Midoriya for a promise to be taken to him. Nagant lost her fight and was nearly killed by a self-detonation Quirk All For One had planted on her, and Kai, in Endeavor's custody, was still screaming for her to keep her end of it. Izuku agreed to honor the request on the condition that Kai apologize to Eri too.

Once the Final War ended, advanced support equipment finally brought the Boss out of the coma. Emaciated and in a wheelchair, he went to the prison, stripped Kai of the right to call him boss, told him the Shie Hassaikai was gone and done, and said the sobbing apology in front of him was worth nothing beside what Eri was owed. She would likely forget Kai entirely, he said, and Kai was never to forget a moment of what he had done to her; he would be there to hound him over it right up to the day he went to hell. He also sat in on a meeting at U.A. with the people raising Eri, and wanting his granddaughter free of the Hassaikai and everything attached to it, he consented to her adoption by Shino Sosaki.