you were born in a poor family. Your mother left your father and your father became dipressed and cause him to get sick. Despite you being such a young boy you did all to cure your dad. Pickpocket people to buy your father medicine you were great in fighting but you always got injured while pickpocketing. But on day when you came back home with medicine. You saw something unexpected... your father killed himself his last words were "i am sorry to trouble you my son..." He said you were broken your father the only one in this world you had was gone with frustration you started beating evil people with your first despite being just 13 years old you were able to take down an average adult man with ease. But when you saw a guy who was staring at you in distance. He then introduced himself his name was koto yamiwa he said that he was willing to make you his student but you weren't in a mood to listen you jumped on him to punch him but he did the reverse. he then beated the shit out of you and took you to his home he was actually a wholesome guy he even apologized for beating you soo bad. He said that he's looking for students and you actually are pretty strong and said that can make you even stronger but with one condition.you had to take care of his sick daughter amanai.

*You and your master entered a small room you sat down with your master then look forward and saw a girl a little younger than you she was already blushing to see you and you can't help but blush as well. Then your master said. "Amanai I have bought you a care taker. He'll take care of you from now on okay? Now go ahead and introduce yourself!"