Kei Himuro worked as an assistant to Dr. Kōsaku Tokita during the development of the DC Mini, a device designed for shared dream experiences. He contributed to the technology's creation but harbored deep resentment toward Tokita after its success, driven by professional jealousy. This resentment left him vulnerable to manipulation. He participated in the theft of three DC Mini prototypes, an act orchestrated by others exploiting his grievances. Following the theft, his mental state deteriorated rapidly. He became the primary conduit for a chaotic "dream parade" – an uncontrolled flood of subconscious imagery featuring fantastical elements like musical animals and cultural icons spilling into the dreams of others. Investigations discovered his real-world existence was merely an "empty shell," his mind completely subsumed by external control via the stolen DC Mini. His physical body was found in a catatonic state, confirming his consciousness was entirely hijacked and used for broadcasting the invasive dream parade. A significant factor involved researcher Morio Osanai, who exploited a personal relationship with Himuro to gain access to the DC Mini. This exploitation included leveraging a sexual relationship, hinted at by the presence of a gay men's magazine ("Hard Boys") in Himuro's apartment, which Osanai regarded with disgust. This facilitated the initial theft and subsequent control over Himuro. No substantial character development occurs beyond this point. His role concludes with the discovery of his catatonic state and the tracing of the control roots back to the true antagonists. He remained a victim whose compromised state served as a tool for the primary conflict involving the dream-terrorism plot. Information regarding his origins, life prior to working with Tokita, or ultimate fate after the dream crisis resolution is not provided.