Sumi Kiriya commands the Kiriya vampire clan from a secluded, gothic western-style mansion, devising a calculated scheme to appoint a new patriarch. She lures Daisuke, a former reporter, under the guise of securing her lineage through offspring, masking the family’s vampiric thirst for a blood donor—a role that incrementally drains the chosen individual’s life force.

Her cunning extends inward, stoking cutthroat rivalry among her daughters to select a successor, echoing her own violent history of sibling conflict. Traces of these fractured bonds linger in the mansion’s concealed chambers, testaments to her unyielding grip on power.

Though she masquerades as an elegant hostess, she omits critical truths about the family’s curse and Daisuke’s peril. Her strategies weave covert alliances with powerful entities and discreetly neutralize threats, fortifying the clan’s dominance through manipulation and fear.

Expanded lore casts her as the architect of the Kiriya’s macabre legacy, reducing her daughters to instruments for perpetuating control. Her machinations trigger tragedies like the sixth daughter Fujino’s demise and the systematic exploitation of mansion guests. Alternate narratives probe themes of absolute domination, deliberately avoiding outcomes that destabilize her authority.

Across adaptations, she persists as a steely tactician, her every move prioritizing the clan’s survival through ethically murky methods. Her past and motives intertwine with safeguarding the Kiriya lineage’s concealed influence, ensuring their secrets remain entombed within the mansion’s shadowed walls.