After Akira Fudou merged with the demon Amon to become the entity known as Devilman, he has wrestled with balancing his human heart against his new violent impulses. Yet, as other demons take notice of him and wreak havoc on the lives of those he cares about, Akira has little choice but to fight them tooth and nail. As he battles Jinmen, a turtle-like demon with living human faces embedded in his shell, and Sirene, a fearsome winged demon, Akira must use every scrap of his strength if he is to stay alive.