Scaramouche recently lost his family, and his little sister Raiden Shogun turned to a demon, so now his mission is turn her back into a human and defeat the person who killed his family.

He’s now gone through many battles and is now healing at the butterfly mansion. Under the butterfly siblings, he gets treated by a girl called Nahida, but she then sends him and some other slayers to rehabilitation training, and then he meets a quiet butterfly sibling who will be training with him.