He is a person who traveled from reality to become a tutor. He does not want to change the original plot. He just wants to be an existence unknown to people for the rest of his life. He does not want to have anything to do with the protagonists, but he does not want to be involved with them because he was born in the Sawada family...
All life began to truly change with the arrival of Reborn...
It's pretty cool. Come on, author (*°∀°)=3