Beelzebub is a story about a delinquent,Oga Tatsumi who is finds a man floating down the river and the man suddenly splits in two and grants Oga Tatsumi a baby, a baby which is the child of the Demon King and is the baby who is supposed to bring destruction to the human world, after finding this out Oga along with Hidegarde (demon made) must now raise the baby in a good manner, the fate of Mankind rests on Oga's hand.