"Urotsukidoji: New Saga" is a dark fantasy anime series that expands on the mythos of the original "Urotsukidoji" franchise, blending elements of horror, erotica, and supernatural action. The narrative revolves around the struggle between humans, demons, and otherworldly beings in a chaotic world where the boundaries between dimensions are breaking down. Central to the story is the concept of the Overfiend, a legendary entity destined to unite the realms of humans, man-beasts, and demons, bringing either salvation or destruction.

The protagonist, Amano Jyaku, is a young man who becomes entangled in the conflict between the three realms. Unbeknownst to him, he is the reincarnation of the Overfiend, a being of immense power whose awakening could reshape reality. As Jyaku grapples with his identity and the forces seeking to control or destroy him, he encounters a host of characters, including Nagumo, a demon hunter with a tragic past, and Akemi, a human woman with a mysterious connection to the supernatural. These characters are drawn into a web of alliances and betrayals as they navigate a world teetering on the brink of annihilation.

The plot delves into themes of power, corruption, and the duality of creation and destruction. The Overfiend’s emergence is both a harbinger of potential unity and a catalyst for chaos, as factions within the demon world vie for dominance. The series explores the moral ambiguities of its characters, with no clear distinction between good and evil. Demons, humans, and man-beasts each have their own motivations, often driven by survival, ambition, or revenge.

The narrative is punctuated by intense action sequences, graphic violence, and explicit content, reflecting the series’ roots in the adult-oriented "Urotsukidoji" tradition. The story builds toward a climactic confrontation as Jyaku’s transformation into the Overfiend becomes inevitable, forcing the characters to confront the consequences of their actions and the fragility of their world. The series concludes with an open-ended resolution, leaving room for interpretation and further exploration of its complex mythology.