The story follows Iruma Suzuki, a 14-year-old human boy, who is sold to a demon by his parents. The demon, known as Sullivan, takes Iruma to the Demon World and officially adopts him as his grandson. He enrolls Iruma in the Babyls School for Demons where he is the headmaster and where Iruma quickly befriends the demons Alice Asmodeus and Clara Valac. However, Sullivan tells Iruma to never reveal that he is human since he will be eaten if anyone finds out. Iruma then vows to blend in during his time in the demon world, although he only stands out because of all the situations and adventures that arise.

Two scientists are attempting to distribute the cure for a demon virus that is affecting people all over Japan, however, things have become complicated. One of them has become infected. So begins his battle with himself, as he attempts to not only control his emerging demon side, but also to save the lives of others by wielding its great strength.

A short web recap of the Devilman: Crybaby series, posted on Aniplex's official YouTube channel.