Ripped this from Reddit, but here's his story: Young Lighter had a family in a mercenary group he was a part of, comprised of a nice old man, this Axl Low looking guy who's probably Dane from the dog tag, this energetic looking lady and a little girl. The merc group bit off more than they could chew and all but Lighter and the kid probably died from him wearing the dog tags Lighter, wanting to fund a life for the kid, went into debt with a Loan shark/mafia to give the kid money to live on, and went to the fighting pit to pay off the debt. There he was undefeated, even winning against the ruling champion, and he became the undisputed champion. This also explains why, in ZZZ, the idea of a "found family" is so heavy to him