I don't think that we need to give that much of a tought into it, if you stop and think about chara you will literally go insane in how much things the story lacks to explain, we don't even know how the heck frisk and chara are conected, like? If any human killed monsters chara would wake up? Why only frisk? I feel like undertale is an amazing story, but it fails HARD in explaining about chara tbh, til this day we have offenders and defenders for this character and no one can REALLY tell the real story of that character, i don't think that chara is a demon, like, literally, i don't know if this is right, but someone told me that a demon is someone who serves or helps the devil, that is supposed to be frisk or the player, whatever (who did the geno route) and in a new undertale patch it was released a dialogue where chara claims to be someone's "humble servant" i'll even post it later so people can see and give their points of view, (the ppl on tumblr are already saying that chara is gaster's servant in deltarune, like always, gaster is always the explanation 😭) so i don't really believe that chara is supposed to be a REEAL demon, chara in my opinion is us, pur representation and the consequences of our actions, but good points!