Amano Jyaku originates from Japanese folklore as an "amanojaku," a heavenly evil spirit known for its contrary nature and ability to provoke humans' darkest desires. He is a hybrid born from a human and a demon, existing as a half-demon or beast-man. He endured intense physical and emotional abuse during childhood, contributing to heightened aggression and a desire for vengeance. Banished to the human realm by The Great Elder of the man-beast world as punishment for misdeeds involving the Elder's daughter Mimi, his core mission spans centuries: searching for the prophesied Overfiend, a being fated to unite or destroy the three realms of human, demon, and man-beast worlds. This quest defines his actions. Significant differences exist between his manga and anime portrayals. The manga depicts him as a sociopathic Villain Protagonist with minimal humanity, frequently manipulating women into sexual encounters, expressing pride in malicious behavior, and casually endangering children. His story concludes with his death in a demon ambush, his body found atop a pile of corpses. Conversely, the anime adaptation grants him Adaptational Heroism, transforming him into an Anti-Hero. While retaining abrasive traits, his anime incarnation demonstrates selflessness, protects others, and survives. His anime motivations are portrayed more nobly, driven by belief in the Overfiend's role in creating peace, though he experiences disillusionment upon learning the Overfiend's true destructive purpose. His key relationships include his sister Megumi Amano, described as "the strongest female of the three realms" – their dynamic is antagonistic in the manga and supportive in the anime. He shares a romantic connection with Mimi Tenno, The Great Elder's granddaughter, whose orgasms project visions of the future. His primary rival is the demon Suikakujū, who opposes the Overfiend's birth to preserve the demon world. He commands loyalty from subordinates like Kuroko of the Kuroko tribe. His character development centers on evolving beliefs and morality. Initially dedicated to the Overfiend legend, he faces profound disillusionment upon realizing its goal is the annihilation of the three realms rather than peaceful unification, forcing him to reassess his purpose. Personality analyses describe him as strategic and assertive, valuing control, self-reliance, and exhibiting a strong protective instinct that can manifest as domineering behavior. He possesses immense physical strength and combat prowess, classified as an Invincible Hero with few capable of challenging him. In *Urotsukidōji III: Return of the Overfiend*, set in a post-apocalyptic world where the Overfiend slumbers, Amano Jyaku survives. He navigates a landscape dominated by the tyrannical Emperor Caesar, who enslaves a new race of demon beasts. The narrative involves the emergence of the Overfiend's nemesis, the Lord of Chaos. Amano Jyaku allies with characters like the redeemed marauder Buju, who becomes the Lord of Chaos's guardian. Their journey involves traveling towards Osaka for a confrontation, facing threats like Caesar's forces and the captured tyrant's daughter.