Seijirō Kanmuri serves as a central figure entwined in a layered dynamic with protagonist Haruto Bouida, balancing rivalry and reluctant camaraderie. Though initially projecting an air of composure, his stubborn devotion to otaku culture mirrors Haruto’s prioritization of fictional bonds over real-world connections. Their clashes frequently erupt into heated debates on anime narratives, contrasting Kanmuri’s analytical skepticism against Haruto’s embrace of the fantastical. As president of Takasago-ya, a manufacturer of hyper-realistic figurines, Kanmuri’s corporate authority directly intersects with the story’s core mystery—the sentient animated figures. Driven by sharp curiosity, he strategically manipulates events, provoking Haruto into debates about the enigmatic Nona and deploying the secondary figurine Bellnoa to probe their supernatural capabilities.

His methods occasionally tip into antagonism, such as engineering hostage scenarios to test figurine powers, yet conflicts with Haruto consistently reset to casual banter, underscoring their unstable alliance. Kanmuri’s appearance—dark hair veiling his right eye, crisp formalwear—echoes his dual identity as corporate strategist and secretive otaku. His name, blending “crown” (冠) with notions of succession, subtly mirrors his narrative role as both challenger and potential guide to Haruto’s journey. Professional obligations and insatiable curiosity about the figurines’ sentience form the extent of his disclosed motivations, with no elaboration on personal history beyond his corporate and subcultural affiliations.