Kirisame, genetically engineered at the Fowler Blanca Institute and once presumed dead, resurfaces months later seeking Koku, a former associate from their shared past as experimental "Promised Children." His return shatters Koku's peace as Kirisame attempts to recruit him into an organization opposing outdated failed experiments like the Reggies. He aims to dismantle systems controlling such beings, advocating a new world order through drastic action.

Kirisame specifically demands Koku's power to eliminate or force the Reggies into self-destruction, leveraging threats against Koku's loved ones to ensure cooperation. He maintains a calm demeanor, manipulating Koku by invoking their shared history and loneliness. His methods include surveillance, psychological pressure, and orchestrated confrontations, exploiting emotional vulnerabilities as a strategic antagonist.

To compel Koku, Kirisame orchestrates the abduction and confinement of Keith Kazama Flick, demonstrating his willingness to endanger lives for ideological liberation. Followers in distinctive clown-like attire assist his plans, though their origins remain undisclosed. Kirisame's storyline concludes with his fate and the larger conflict unresolved.