Talk:Chara/@comment-3040277-20151130055338/@comment-6086723-20151203220914

Somewhere here, in Chara's page, it says that, in the start of the game, you're possibly naming Chara's (As 'Chara' seems to be the short of 'Character') real name, as his name during the story is no more than "The fallen child" or "The first human".

Again, in the page says that possibly Chara's soul was put into Frisk's body as he fell into his grave (The bed of flowers).

I think those theories match quite perfectly.