Komada is a molecular biologist and university professor who works alongside his colleague Koshigaya. Beyond academia, they work as covert agents combating a demon virus that transforms the infected into monstrous entities driven by predatory instincts. Komada becomes infected during a mission.

Unlike typical victims who fully transform and lose their humanity, Komada uniquely retains partial control over the virus. Through intense willpower and strict regimens like specialized diets, he suppresses its corruptive urges, maintaining his consciousness and human identity while accessing the enhanced physical capabilities and strength of his demon form.

Infection manifests physically through involuntary reactions, such as tearing up near other infected individuals, acting as an early detection mechanism. Transformation brings distinctive alterations, including red eyes. While full transformation grants significant combat prowess, it risks accelerating the virus's consumption of his humanity. Each use of his demonic abilities erodes his control, creating constant tension between utilizing this power and fearing permanent loss of self.

A pivotal confrontation occurs against Seijuro Tabe, a powerful demon-possessed politician. To prevail, Komada deliberately synchronizes with the virus at a deeper level, achieving a fused state that maximizes his power but permanently alters his existence. This fusion ensures his survival and victory at the cost of becoming something neither fully human nor demon, carrying an enduring burden of isolation.

Following this event, Komada consciously distances himself from personal relationships and potential happiness, prioritizing his role in containing the virus over normalcy. His existence becomes defined by vigilance and the ongoing struggle to balance his fractured identity against the responsibility of protecting others from the infection he carries.