Ria, a supernatural entity from a non-human realm, is summoned into the human world through occult rituals conducted by Hideya. Her manifestation arises from his prior invocation, linked to his ambiguous desires, though shifting circumstances lead him to reject her aid once she arrives. Undeterred, she clings to the summoning pact’s obligations, refusing to depart despite his resistance.

Before crossing into the human world, she bid farewell to a companion named Selina, hinting at bonds forged in her original realm. Though rooted in the mystical, her nature intertwines fragility and resolve—she displays raw distress when spurned, yet persists in weaving herself into Hideya’s life through persuasion and stubborn loyalty. Their relationship shifts from friction to fragile alliance as she insists on honoring their pact, and he begrudgingly tolerates her presence.

Her role centers on sparking tension, both interpersonal and situational, as she navigates human dynamics with the duality of her existence: an otherworldly being bound by ritual, yet achingly vulnerable in her yearning to fulfill a purpose now questioned by the one who summoned her.