Yūya Kuroki stands as a central figure and younger brother to Takuya Kuroki. Abandoned by their parents in childhood, both siblings were raised by the Special Weapons Enforcement (SWE), a government unit suppressing ideological crimes, including supernatural beliefs. Immersed in this environment, Yūya initially embraced the state's denial of spiritual energy, actively participating in SWE operations without question.

Yūya possesses undefined psychic abilities. Unlike his aggressive and resolute brother Takuya, he exhibits a pacifistic nature. This disposition proves critical during the climax, where he advocates severing the connection between their pair and the Kirihara brothers, Naoto and Naoya, instead of employing lethal force. Despite his intentions, this act inadvertently triggers catastrophic consequences for their world.

Yūya grapples with fragmented visions of his childhood separation, interpreted as memories but prominently featuring adult versions of the Kirihara brothers. This fuels a personal vendetta against them. The finale reveals these visions were not recollections, but premonitions of future events. The truth emerges that during a SWE raid on their home, Naoto Kirihara intervened to protect Yūya and his family, contradicting Yūya's belief that Naoto caused their parents' deaths. The raid injured their mother with broken glass, though she survived, while the brothers were taken into state custody.

Through interactions with the Kirihara brothers and the mysterious Shoko Futami, whose guidance proves pivotal, Yūya undergoes significant development. Her message ultimately enables his reconciliation with his parents, facilitated by the Kirihara brothers' self-sacrifice. This resolution allows Yūya to move past his misconceptions and embrace the necessity of balancing material and spiritual forces.