Disgaea 4 has a new feature that allows you to fuse two monsters together to make a bigger more powerful monster that has larger AoE range. For example the Prinny's first ability Prillin Bomb that originally hits one space turns into a skill that hits a line of three spaces instead. The stats are determined by adding 30% of the monsters Base (Unequipped) stats to the monster you are fusing into unless you are using the fusion lover innocent where it uses 55% of the monsters stats. A evil symbol allows you to use 30% of a monsters Modified(Equipped) unless again you are using the fusion lover innocent which gives 55% instead.