Hikaru Sudō is a human medical doctor specializing in treating humanoids—advanced AI entities with human-like physical forms and consciousness. He operates the Sudo New Medical Clinic, addressing unique ailments affecting these patients. In appearance, he possesses silver-white hair and silver eyes, typically wearing a black turtleneck, gray pants, black shoes, and a white coat in his office. His childhood trauma stems from a rare, serious disease. His adoptive mother, a humanoid, participated in an illegal study trading her unauthorized mind backup for his treatment. The original was imprisoned for this crime, profoundly shaping Sudō’s life. This fuels his unresolved quest to locate his mother’s copy, driving his actions. Under the pseudonym "Moggadeet," he performs illegal medical procedures for humanoids unable to seek conventional care. This clandestine work addresses complex ethical cases while gathering intelligence on his mother. He charges substantial fees to fund his search. Professionally, he maintains a cool, detached, and analytical demeanor, though his dedication reveals underlying empathy. He confronts ethical dilemmas directly, like restoring humanoids from illegal backups—which erases recent memories and challenges identity continuity. He prioritizes practical solutions over emotional comfort, openly discussing these complexities with patients and families. Interpersonally, he shares a reserved yet professional relationship with his clinic assistant, Risa Higuchi. Tensions occasionally surface, such as Risa’s jealousy over his familiarity with Kaoru, a nonbinary humanoid he previously collaborated with in a lab. He respects Kaoru’s identity, stating they are "neither" male nor female when questioned. Personality assessments categorize him as an INTP—introverted, analytical, and intellectually curious—and an Enneagram 6w5—cautious, loyal, and knowledge-oriented. These traits manifest in his problem-solving focus, skepticism toward societal norms about humanoids, and preference for logic over emotion. His caution, rooted in childhood trauma, drives meticulousness in both legal and illegal work. His development centers on reconciling his human identity in an AI-integrated world. Despite noted displays of prejudice toward humanoids, his actions consistently advocate for their personhood and ethical treatment. This duality reflects tension between his traumatic past and his commitment to navigating human-AI relationships.