The son of the Devil King. He is very attached to Oga, clinging with a vice-like grip to Oga's back. When he is agitated or sees blood, he will spontaneously electrocute anyone within his vicinity. Beelzebub's characteristic cry is "Daabuu!" and he is always naked with a pacifier in his mouth.

Baby Be'el is very easily impressed, especially by strong people since he himself is still weak and loses to other babies as well as to cats. On the other hand he is not the smartest one out there and tries to force his way through the most simple problems. It is also shown that he is afraid of insects. He often displays a fondness for things that might frighten "normal" babies, such as violence, exposed muscle tissue (on an anatomy model), heavy metal music, and demonic toys.