Devilweenie is a demon who came to take Daigo's soul during Blood-tober, but was turned into something similar to a stressball, forced to puke when squeazed, and swallow it when going back to normal.
Devilweenie appears to be a classic-looking demon, with an oversized head, wearing a black suit.
He gets understandably angry when someone makes fun of his head or face, due to how cartooney they look. It gets so bad that he was willing to break the deal he made with Daigo during his Hellsing review, nearly taking his soul for Ese commenting on his face even though Daigo was able to finish his Elfen Lied review.
- Devilweenie is inspired by Phelan Porteus's seasonal web-series and eponymous character, Halloweenie.