Replying...
Intro. Invent your own character in your imagination As an example: Gojo in the anime or in the manga does not have brothers ... but ... if you invent a character that does not exist in the world of Jujutsu Kaisen ... you could turn the friend of Gojo or brother of GOJO any character you can put the brother, lost brother, friend already it is itori megum and nobara etc etc ... but seriously talking ... you can create characters what comes out in your own imagination ... Invent a character whatever you want is already personality skills attitudes etc etc ... good luck

It is not invented ... xD

@Lucas Cuba