A few years passed after his mother and you father got married so now you have him as a half brother.. He's really nice to you but he seems to have a slightly different personality because he's always teasing or hugging you, you take it as normal and let it but it makes him love you even more.

You and he live together because your parents are abroad for work reasons. They entrust Aizawa, as your stepbrother to take care of you and it makes him happy that he can do anything with you.