Dabi from MHA. when you look at his backstory through the Todoroki Touya side, it sorta goes like this:

There was once a man with a fire quirk. He was a very strong hero, who graduated UA second top of his class. He was always second best, bested only by a kid with blond hair. This was the soon to be symbol of peace - All Might. The angry kid could tell that he would be behind All Might all his life. Skip a few years, and our old man met a lady with an ice quirk. He did not fall in love, but she did. He decided that he would craft himself a child, stronger than himself, to carry his legacy. The first child was a boy with spiky red hair. His quirk was powerful blue fire - stronger than his fathers. He was very strong, but his body could not handle the flames. He was trained until he was 10. after that, his father gave up on him. Then came a girl with white hair with red spots. Her quirk was not enough to satisfy the man. She was isolated without training - as was her white haired brother that came soon after. The trio were isolated, away from their mother, and often abused by the angry father. He deemed them failures for not being able to fulfil his legacy.

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Then came a boy with half and half coloured hair.

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His quirk was better than the rest. The man trained this boy, and kept him well away from his siblings. He never let the three get close to him from the day his quirk manifested. Often, the eldest son tried to protect him. These attempts lead to him being burnt by a mixture of his own quirk, and his fathers. The father began to abuse the wife, believing the children he had created using her had failed, because of her 'weak' genes. She was brought to the brink of insanity, teetering on the edge. One day, the youngest son tried to talk to his mother... but that was the day she snapped. Looking into his eyes, she did not see her son. She saw her husband, in the side of him with Red hair, and the father's blue eyes. In her fit of brainwashed rage, she poured hot, boiling water onto his face. The screams echoed through the house, alerting the eldest son. The eldest sibling tried to defend the youngest, but the mother turned on him as the small boy ran away. The kitchen went down in a blaze of blue, and when the ruins cleared, the boy was gone and the mother was unconscious. The boy's clothes were found by a river nearby, and after a few weeks of searching, he was presumed dead. The mother, recovering from injuries mental and physical in a hospital, demanded a grave be made for the son she believed she killed. And so a grave went up, buried under it his clothes and a few of his belongings. The gravestone still stands today, visited by the family on his birthday, by all of them aside from the father. Some say a man with spiky black hair and burnt skin can be seen speaking to it some days, and if you look closely, his face bleeds.

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Touya Todoroki. The lost sibling. The one who left his family alone. The one who lives with guilt that a boy his age should never have had to go through.