"Twilight of the Dark Master" is a dark, cyberpunk OVA set in a dystopian future where humanity coexists with supernatural entities known as Shiki. The story centers on Tsunami Shijo, a powerful and enigmatic Shiki hunter, who becomes entangled in a conflict involving a rogue Shiki named Shido. Shido seeks to harness the power of the "Dark Master," an ancient and destructive force capable of reshaping the world. As Tsunami investigates Shido's plans, he encounters a young woman named Reiko, who possesses a mysterious connection to the Dark Master. Their fates intertwine as they confront Shido and his followers, who aim to unleash chaos by reviving the Dark Master's power.

The narrative explores themes of power, corruption, and the blurred lines between humanity and monstrosity. Tsunami's stoic and morally ambiguous nature contrasts with Reiko's vulnerability and determination, creating a dynamic interplay between the characters. The plot unfolds in a gritty urban landscape filled with violence, supernatural battles, and political intrigue, as various factions vie for control over the Dark Master's power. The OVA delves into the consequences of unchecked ambition and the cyclical nature of destruction, culminating in a climactic confrontation that tests the resolve of its protagonists. The story's pacing is brisk, with a focus on action and atmosphere, while leaving room for moments of introspection and character development.