Zennon is a much feared and ultra-powerful demon, normally filling the role of either the leader of the demons or another high-ranking position. He appears in the majority of the adaptations of Devilman. Zennon's name and role as a demon lord derives from a similar character in Demon Lord Dante; his appearance however was reused for the character Zannin in the Devilman franchise proper.
- Zennon: Second in command of the demon army along with Psycho Jenny. He rarely directly impacts the story, but is the subject of several nightmares of Akira Fudo and is the one to to announce the arrival of the demon race to the human world. He also appears in Devilman Lady.
- Zennon (TV): The main antagonist of the Devilman television series. The leader of The Demon Tribe, he often stayed in in the shadows as his soldiers did his dirty work.
- Zennon (OVA): The briefly seen second in command of the demon race.
- Zennon (Grimoire): The Devilman form of Ryo Utsugi and a mighty demon in his own right.
- Zennon (Hiruta): The leader of the Demon Tribe, Zennon is the true antagonist of the manga.
- Zennon (Isako): The main antagonist of the Isako Manga.
- Zennon (Toshin): The main villian of the manga Toshin Devilman.
- Zennon (Dynamic Heroes): Briefly seen in a flashback of Devilman's as he thinks back to his past foes.
- Zennon (CB Chara): Satan's second in command, and somewhat less threatening than his previous incarnations.