Akuma no Hiroigo

Belial is a low-ranking demon content with his life in the underworld. Sure, sometimes he doesn't have enough to eat, and his devilish peers strive for more power. But, Belial manages to live his best (demon) life. When Belial discovers what appears to be an abandoned human baby, he looks forward to the prospect of a fresh meal. But, after this "baby" quickly transforms into a grown boy in the flash of an eye, Belial realizes that maybe what he found wasn't human at all... Official English Translation