In the vibrant heart of Tokyo, where vampires casually stroll the streets, Aruno Kurogane, the Vitanex, emerges from a mystical portal, stepping into a world where supernatural forces and everyday life intertwine. Leading an ostensibly ordinary existence, Aruno's arrival coincides with the awakening of demonic entities, breaching the veil between dimensions. As Japan becomes the battleground for ancient forces, Aruno must navigate a metropolis where vampires are commonplace, uncovering his own role in the impending clash between worlds.