User blog comment:BNHATrash420/Reasons Why Todoroki And Dabi Are Actually Brothers/@comment-38472715-20190416020717

If you look him up, he used to have red hair and a fairly chiseled face, not unlike our boy Shotuo. I agree with the theory that he was abused by Endeavor, and his real name is actually Touya Todoroki. Therefore, Dabi (Touya) is Todoroki's brother. I own the manga, and there's no extra info in them, so don't bother searching. Hope I could help!