Easily Pennywise, Champ is more hateful but Pennywise mind rapes, tortures and eats children and adults on a daily basis.

Champ is an awful scumbad, but It has done so much worse.

Haven't watched Akame Ga Kill! (and I don't intend to because it sounds extremely dumb and edgy like a lot of other anime) but Champ sounds morally worse to me.

Pennywise needs to eat humans in order to survive and it tortures its food to make it tastier. It is not very clear to what extent its actions are caused by its nature and it is possible that it has moral agency issues because its backstory is never explored.

Champ has a lot less resources than Pennywise, his actions are not caused by his nature and he doesn't need to rape and kill children to survive, so I choose him.

You could say that with almost any PE vs Pennywise though, it's not in their nature to do it but Pennywise is so cruelly sadistic in his actions.