Board Thread:Wiki Discussion/@comment-25958552-20160731111602/@comment-25648422-20160731132913

I don't think Asriel's SOUL is responsible for "corrupting" Chara. I doubt that is one of the functions of a SOUL, whethet it is a monster SOUL or a human SOUL

At the end of the True Pacifist Route, Asriel told Frisk that Chara hated humanity and that Chara wasn't the greatest person. When Asriel said that, I don't think Chara seems to be immediately bad. Then again, she laughed it off when Ashore was poisoned by accidentally eating buttercups so either Chara was bad or just simply mean.

The only time Chara was bad, or evil, is in the Genocide Route, when she decided to take advantage of Frisk when the latter became murderous and used that advantage in order to posses him as well as when Chara finally appears at the end of the route, in which she gives the option to erase or not erase the world. To add further insult to injury, Chara will still erase the world and screw up your game even if you refuse to have the world destroyed. Heck she would even ask for the protagonist's SOUL if you want your game to be fixed.

So in my opinion, Chara does not seem to be bad from the state. Only certain events that happened in Undertale is what causes Chara to turn into a heartless being.