Amano Jaku originates as a demon-human hybrid banished to Earth as punishment for misdeeds against the Great Elder and his daughter Mimi. His manga mission requires locating the Chōjin, a powerful deity hidden within a human, to protect it from reptilian demons led by Suikakuju who seek its power for the Demon Queen. This manga version depicts him as manipulative and morally ambiguous, frequently using deception like claiming protective properties for his sperm to coerce women into sexual encounters. The anime adaptation transforms his role and personality. Belonging to the man-beast realm, he serves as the primary protagonist. His mission expands to finding the Chōjin to unite three worlds—human, demon, and man-beast—into peaceful coexistence. This version portrays him with greater nobility and dedication to the prophecy, confronting profound ideological challenges when events contradict his long-held beliefs about the Chōjin's purpose. His relationship with the Great Elder shifts from banishment to mentorship, with the Elder aiding his quest. His familial relationships also differ between media. In both, his sister Megumi joins him on Earth, displaying nymphomaniac tendencies. The manga depicts Megumi as malicious and antagonistic, framing men for rape or consuming them after seduction, while the anime softens her into a more empathetic figure who develops genuine romantic feelings for a human. His romantic involvement with Mimi, the Elder's granddaughter, remains consistent; her orgasms trigger prophetic visions crucial to the plot. In later OVA installments like *Return of the Overfiend*, Amano Jaku navigates a post-Overfiend-apocalyptic landscape. He allies with Buju, a reformed demon-beast marauder, and others against the cyborg tyrant Caesar. These narratives focus on his survival and protective role toward the Overfiend's offspring amid new conflicts, showcasing his endurance and adaptability. Physically, he is consistently depicted with dark violet hair and black eyes across all media. His development reflects a broader narrative arc: from self-serving antihero in the manga to a disillusioned but resilient warrior in the anime continuations, continually grappling with destiny and violence while pursuing redemption or purpose.