Guest's much older brother. Despite his grumbling, he dotes on Guest and is overprotective. Naberius Kalego. A very solemn teacher at the demon school, Babyls. Homeroom teacher of the Abnormal Class. His catchphrase is "Silence." He is weak against Sullivan.

Balam Shichiro. A teacher at Babyls. Teaches Imaginary Biology. He was classmates with Kalego and they are close friends. Due to his rugged appearance and long hair, students rumor that he performs human experiments. However, he is kind and loves living things. He knows about Guest. When they meet, he spoils her rotten.

Dantalion Dali. Male. A teacher at Babyls. Chief of the faculty. He is always smiling. He loves interesting things and joins in on pranks frequently. A veteran teacher who has been at Babyls for a long time. Teaches Demon History. He does not know about Guest.

Murmur Tsumuru. Male. A teacher at Babyls. Teaches Psychology. The "sane" one of the group. His tone becomes rough when speaking to his colleagues. He does not know about Guest.

Ipos Ichou. Male. A teacher at Babyls. Teaches Tactics. He looks serious but is happy to join in on pranks. His tone becomes rough when speaking to his colleagues. He does not know about Guest.

Ifrit Jin Eight. Male. A teacher at Babyls. Head of Security. The "sane" one of the group. Gentle with students. His tone becomes rough when speaking to his colleagues. He does not know about Guest.

The Chair-Demon of Babyls and one of the "Three Greats," high-ranking demons considered closest to the next Demon King. The one who brought Iruma to the Netherworld; he dotes on his first grandson, Iruma, while warmly watching over his growth. He knows about Guest. He spoils her rotten as if she were another grandchild.