Susumu Yamazaki serves in the Shinsengumi’s intelligence unit, defined by a pragmatic, duty-driven approach. Initially portrayed as reserved and keenly observant, he navigates dual roles as a spy and medic, tending to comrades’ injuries while gathering information and safeguarding operations. His wariness toward newcomers like Chizuru Yukimura stems from ingrained caution toward potential threats to the group’s security. Beneath his guarded exterior lies unexpected gentleness, gradually revealed through his growing concern for Chizuru. In dedicated narratives, his unwavering loyalty to the Shinsengumi evolves into a deeper commitment to her safety, culminating in his departure after the Battle of Toba-Fushimi. He abandons military life to establish a clinic in Edo with Chizuru, where they pursue Western medicine and language studies, striving to counteract his Rasetsu condition—a consequence of consuming the Water of Life that threatens his longevity. In *Hakuouki: SSL*, his modern-day counterpart mirrors this seriousness as a studious high schooler determined to enter medical school. His bond with Chizuru transitions from camaraderie to quiet romance, expressed through supportive acts like aiding her during Valentine’s Day or sharing contemplative moments during the year’s first sunrise. Interactions with peers such as Okita and Sannan showcase dry wit and occasional exasperation, echoing his historical persona’s blend of stoicism and subtle warmth. Diverging from history, certain narratives permit his survival, avoiding his real-world fate. Rejecting the Shinsengumi’s symbolic haori and favoring Western attire underscores his practical focus over ceremony. Though younger than his historical namesake, his story intertwines sacrifice, loyalty, and redemption through healing, emphasizing action over tradition. As a Fury, his enhanced abilities come at a cost: accelerated physical corruption from their use. Storyline choices pivot on managing this decline, with endings ranging from tragic self-sacrifice to hopeful resolutions where he chooses a future with Chizuru over martial honor. This tension between duty and personal yearning underscores his internal struggle, balancing the weight of responsibility against the desire for a peaceful life.