The youngest, cheekiest, and most cunning of the demon brothers. Until a certain incident took place, he respected Lucifer the most among his brothers.

Belphegor sometimes has a brisk temper, but he's also proactive, efficient, sensible, and mellow. He isn't particularly sociable, but makes an exception for MC, who he likes to cuddle and take naps with. He also lies about the fact that he doesn't like to be pet. He isn't the type to say sorry or accept apologies from others.