Identical to some headcanons of the first fallen child, except called Bacon. They prefer being called Chara, however.
They firmly believe that killing will solve every problem that comes their way. Frisk hypothesises that this is because Bacon is lonely and, as killing people will turn them into ghost, they'll have friends. Bacon's reaction to this however suggests this is not the case. Later Frisk changes their mind and believes that Bacon hate humanity because their parents called them Bacon... which is a fair assumption.