Zool was a short green demon, instead of legs he travelled on a slug like tail, he had a stubby beak and weary red eyes with yellow pupils, he has large white eyebrows and a large green fin decorating the top of his head. His whole body was covered in small lumps and a thin layer of sharp teeth layered his drooling mouth.
Zool could craft sculptures of humans that would cause the person they were modelled after to die violently when the sculpture is destroyed.
Zool was a very dim-witted and scatter brained demon, but was a highly skilled artist with great power, which could of been used to great ability had Zool been any smarter. In spite of Zool's ability, it is hindered by his incredibly sadistic nature and frequent childish tantrums.
After the failure of many demons before him, Zool was summoned by Demon Lord Zennon who commanded him to create a model of the one Akira Fudo loved the most, Miki Makimura, and then destroy it, which would in turn kill her. Zool agreed to but needed a picture of Makimura to work from, with that Zennon called upon the fire demon Abil to assist Zool and get a picture of the girl.
Zool steals a painting of Miki from a pretentious art student named Iwao Himura and give it to Zool who begins on his sculpture. After completing it, Zool begins to torture the doll, causing the real Makimura agonising pain, however before he can get to far Abil comes in and forbids him from going any further and plans to destroy the doll in front of Devilman to break his will instead. Frustrated, Zool begins smashing his figures, tossing a large boulder onto one, which called a colossal meteorite to form into reality and crush the man the model was made of.
At a similar time, Akira realises why Abil stole the portrait and rushes to Zool's cave to confront the two demons. Sensing his approach, Abil orders Zool to get the Miki doll ready before he goes out to fight Fudo. Zool searches for the doll but realises he had lost it and begins to panic. In spite of putting up a good fight, Abil is slain by Devilman, and dies wondering why Zool never arrived with the doll. Akira finds Zool in his cave, still searching for his doll. Realising the game was up Zool begs for mercy, but his pleas are ignored as Akira beats him down and then kills him, by impaling him on a stalactite.
- Zool's death is exactly the same as Daruni, a similarly gluttonous demon that appeared in the first episode of the Devilman anime.