Kotaro Shimura

In childhood he was missing a front tooth, his hair dark, his clothing nothing more than a T-shirt and sneakers.

By adulthood the hair was cut short with a cowlick standing up on the right side. His clothes were black trousers and a polo shirt patterned in stripes.

The boy was ordinary and content, close to his mother. Being surrendered to foster care turned that sadness into resentment and then hostility, since it read to him as her abandoning him selfishly to chase hero duties and save strangers. From there it widened into a loathing of every hero, all of them selfish people whose work only ever damaged their own families.

Acting on that hatred, he banned any mention of heroes from his house and turned violent, emotionally and physically, whenever the rule broke. Hana, nearly caught having entered his office, panicked so badly that she blamed her brother to save herself, which suggests earlier punishments had been harsh. Convinced Tenko was the one who snuck in and found a photograph of him with his mother, Kotaro attacked his son and tore down the grandmother's memory, justifying it by insisting his children could not be allowed to idolize heroes, Tenko least of all since no Quirk had appeared in him. He framed it as sparing them worse suffering later. The irony is that he became exactly what he accused every hero of being, and in doing so planted the loathing his son would carry forward.

Cold as he was, he was not without conscience. He came to question how he treated his family and felt remorse for hurting his child, and Nao says he wanted a happy family, which implies the abusive father was not what he set out to be. Even his resentment held grief: reading his mother's letter beside a photo of the two of them, he wished she had never loved him, since that would have hurt less. None of it stopped him from reaching for violence first when Tenko lost hold of his awakening Decay, striking his son with a weed clipper, a choice that cost him his life.

Responsibility stays with him, yet he was himself manipulated. Never knowing the man's identity, he grew close to All For One, a friendship that produced Tenko and pushed him toward greater strictness, since the villain approved of his methods and cultivated the resentment already there. He was not a poor father from the start, and his dislike of heroes never curdled into true hatred until it was steered.

Nana Shimura and the husband whose name is unrecorded had exactly one child, and that child was Kotaro. A brief, happy childhood ended when a villain killed his father and his grieving mother placed him in foster care rather than let him meet the same fate. To keep All For One away from him, Nana altered the family register to erase the link and made her friends and students Sorahiko Torino and Toshinori Yagi swear never to seek Kotaro out.

He grew up, married Nao Magi, and had a daughter, Hana. Success in business came early, and he put up a spacious home for them all, inviting his in-laws to move in as well. Somewhere along the way he befriended a man from Koga Constructions, unaware this was All For One, his mother's killer. Knowing his history and his bitterness, All For One told him that heroes stay absent precisely when they are wanted, which is why a child needs a sibling to lean on. Kotaro took the advice at face value and fathered Tenko. All For One had already stolen the boy's original Quirk Factor without his knowledge, leaving Tenko Quirkless, and kept quiet watch over the family.

Following that guidance, Kotaro forbade the concept of heroes at home entirely, and Tenko's fascination with them meant frequent punishment. One day he realized his children had been inside his office, and he rounded on his son over the photograph of their grandmother. Enraged, he attacked the boy, spat out his disgust for heroes and his mother's legacy, and left Tenko sitting outdoors after nightfall while his horrified family looked on. Afterward he sat with the photograph and the letter, and when Nao and her parents came to him he already knew he had gone too far.

Later that night, the Decay Quirk All For One had secretly planted in him days before slipped out of Tenko's control, killing the family dog Mon and then the household. Drawn by the noise, Kotaro found the carnage as his son begged for help. With the Quirk eating the area and Tenko reaching for him, he attacked to make it stop, which triggered the boy's instincts and turned him murderous. Tenko touched his face and killed him in payment for the pain, destroying the house and relishing it.

His orphaned son wandered until All For One found him and renamed him Tomura Shigaraki. All that remained of Kotaro was the severed hand worn on his son's villain costume, crushed eventually as Tomura broke from his past. He surfaced afterward only as a vestige in his son's mind, looming once to shout at him over the study, later emerging from All For One's shadow with the rest of the Shimuras to hold him back. During the Final War, as Tomura's body warped under the Quirk Singularity, the family's faces appeared on his left hand, and Izuku Midoriya read in them the proof that Tomura was still fighting from within.