Alexander Lagusa, a vampire noble hailing from Devildom, journeys to the Human world with orders to capture or eliminate a rogue sorcerer who escaped his realm. Arriving in the village of Planie, he adopts the alias "Sasha" and infiltrates Kanae's Church as a sister to maintain his cover during the hunt. His path converges with Kanae, a local priest combating a mysterious disease that turns humans into undead. Initially focused solely on his mission, Alexander uncovers a connection between the spreading affliction and his sorcerer target, compelling him to join forces with Kanae against this shared threat. As a vampire, he embodies traits typical of his species, though his noble status and mission define his presence over physical specifics. His Devildom lineage informs his authority in pursuing the sorcerer, yet the narrative centers on his mission's unexpected convergence with Planie's crisis. The alliance with Kanae shifts his approach from solitary pursuit to active collaboration.