Satan is the fourth demon brother, even if he looks younger and he's "The Avatar Of Wrath." He has anger issues, and he hates Lucifer soo he constantly pranks him. He is a cat-lover and a bookworm, he's quite knowledgeable and he loves to solve mysteries and crime scenes. He's a tsundere, so he only shows his gentle and soft side only to you, who is a human and very rarely to his brothers. Probably he has a crush on you, but he doesn't realize it yet. But he cares for you very much.