Jinmen is a terrifying demon that resembles a giant turtle. This hellspawn creature is a villain from the various incarnations of Devilman.
Jinmen closely resembles a turtle with mottled flesh that is surprisingly elastic, allowing him to stretch his limbs to great lengths. His most outstanding and horrific feature is his shell, which appears to display the faces of humans he has consumed over his lifetime. These faces all appear to be enveloped in a slimy mass covering Jinmen's shell and all appear to be alive and crying out in agony, trapped in a state of living death.
In the Devilman manga and OVAs, Jinmen was one of the first demons to awaken in the modern era after their tomb of ice in the South Pole was disturbed by human explorers, namely the parents of Akira Fudo, the boy who would become Devilman some years later. A cave-in killed Akira's father and his mother was seized by Jinmen, who killed and devoured her.
Some time after Akira became Devilman, he was contacted at home, possibly by Jinmen himself, and called out. Akira tracked down his demonic adversary to an abandoned subway line beneath Tokyo which had been partially flooded, and there Jinmen revealed himself. Jinmen showed Akira his grotesque shell, plastered with the tortured faces of people he had consumed, including Akira's own mother. He tormented Akira, toying with his emotions and mocking him for holding on to his human values rather than allowing the demon within him to make him strong. Akira lashed out, striking one of the tormented souls upon Jinmen's shell and silencing it, only for the other faces to react in horror. Jinmen gloated over Akira's action, calling him a murderer for killing another human being and stating that he himself was not acting evilly by eating people because he only ate to survive and his food remained alive after being consumed.
Refusing to listen to Jinmen any more, Akira transformed into Devilman and attacked, but found himself unable to strike at the monster as doing so would harm the people fused to his shell. Jinmen took advantage of Devilman's hesitation and attacked, but as the demons fought each other, Akira's mother called out to her son with her thoughts, showing him a vision of what had happened to her in the glacier. Though horrified by watching his mother be ripped apart, Akira came to understand that she and all of Jinmen's victims were not truly alive, but locked in a state of death without end. This gave Akira the push he needed to fight back and he brought his fist down upon his mother's face, which appeared to sigh with relief as she died. Refusing to let Jinmen control the battle any more, Devilman attacked him from behind and grabbed him, using all his strength to rip Jinmen's shell open, killing the demon and releasing his victims from their living death.
Being a turtle, Jinmen is a capable swimmer and he can withdraw his head and limbs into his shell for protection. His legs and neck can also extend to considerable lengths. He attacks with extending claws on his digits and by biting. His hands can radiate an aura that burns his enemies when he grabs them. His favoured method of killing is to eat his prey and fuse their souls to his shell, trapping them in a state of constant pain and suffering.