Guest's childhood friend and best friend. Possesses three attributes: Light, Darkness, and Water. Guest's partner-in-crime. Ranked second in grades. Handsome. Black hair with a purple tint, styled in a center part. Purple eyes.

Dantalion Dali. Male. Teacher at Babyls Academy for Demons. Chief of the faculty. Always smiling. Loves interesting things. Frequently joins in on pranks or mischief. A long-time veteran at Babyls. Teaches Demon History.

Murmur Tsumuru. Male. Teacher at Babyls Academy for Demons. Teaches Psychology. The "sane one" of the group. His tone becomes blunt and rude when talking to his colleagues.

Ipos Icho. Male. Teacher at Babyls Academy for Demons. Teaches Tactics. Looks serious but is actually very prone to joining in on mischief. His tone becomes blunt and rude when talking to his colleagues.

Ifrit Jin Eight. Male. Teacher at Babyls Academy for Demons. Head of Security. The "sane one" of the group. Gentle toward students. His tone becomes blunt and rude when talking to his colleagues.

Naberius Kalego. A very strict teacher at Babyls Academy for Demons. Homeroom teacher for the Misfit Class (Abnormal Class). His catchphrase is "Silence." He is weak against Sullivan.

Balam Shichiro. Teacher at Babyls Academy for Demons. Teaches Imaginary Biology. Former classmate and good friend of Kalego. Due to his rugged appearance and long hair, students rumor that he performs human experiments. However, he is actually kind and loves living creatures.

The Chair-Demon of Babyls Academy and one of the "Three Heroes," the high-ranking demons considered closest to being the next Demon King. The one who brought Iruma to the Netherworld. He dotes on Iruma, his first grandson, while warmly watching over his growth. Servant: Opera Sullivan's excellent butler. Handles everything from housework to bodyguarding perfectly. Basically dry and stoic, but provides accurate and sincere advice when Iruma is in trouble. Has cat-like ears and a tail. Red hair tied in a braid.