Monster

The Monster is an evil spirit that appeared in the Devilgram Say His Name. As of now, this character has not appeared in any other Devilgrams or in the main storyline.

Story
Note: this section may include spoilers

After MC presents Beelzebub with a mountain of cheeseburgers, one of them seems to be possessed by a monster. Said monster devours both MC and Beelzebub and would only release them after Beelzebub guessed its name.

Little is known about the monster, but it is very hostile toward humans and especially volatile towards Beelzebub for forgetting it. It also knows the brothers, Diavolo, Barbatos, and Solomon, and holds negative views towards them. It loves sleeping and its younger sister.

At the end of the Devilgram story, the monster is revealed to be a manifestation of Belphegor.