Yuki Hanzōmon, codenamed Hanzō, hails from a martial lineage as heir to a dojo. Her childhood was defined by relentless daily training with a bamboo sword, forging exceptional combat prowess. This skill drew the attention of Nagaho Fujibayashi, who recruited Yuki into the covert agency Tsukikage after personally defeating her unarmed. This pivotal moment launched Yuki's path as a spy sworn to protect Sorasaki City. Under Nagaho's mentorship, Yuki honed her abilities relentlessly, ascending to become one of Tsukikage's most formidable operatives, driven by a profound dedication to her city's safety.

A critical mission infiltrating the Moryo organization alongside Nagaho culminated in a clash with the antagonist Sparrow Woman. Nagaho sacrificed herself, throwing herself in front of a fatal blow meant for Yuki and dying before her eyes. An ensuing explosion sent Yuki tumbling down a staircase, leaving a scar across her right eye. This devastating loss reshaped Yuki, prompting her to adopt a colder, emotionally detached demeanor as armor against future attachments and the pain of loss.

Physically, Yuki possesses long blue hair, typically secured in pigtails with white flower scrunchies. Her bangs partially obscure the scar over her functional right eye, complementing her purple eyes, which shift to bright yellow when Spyce enhances her. She commonly appears in her Sorasaki High School uniform or Tsukikage gear, though she also wears casual clothes. The scar remains a constant reminder of her trauma.

Leading Tsukikage, Yuki operates with cool composure and rationality. She leverages sharp intuition and analytical skill to swiftly assess situations and strategize. Highly perceptive, she excels in intimidation-based interrogation, prioritizing logical decisions above all. Her strictness, particularly as mentor to apprentice Momo Minamoto, stems from a deep-seated desire to prevent others from suffering loss as she did. Beneath her detached exterior lies kindness; she readily acknowledges others' achievements, celebrates birthdays, and apologizes for misjudgments, highlighting her internal conflict between suppressed emotions and genuine care.

In combat, Yuki wields a Japanese sword with considerable proficiency, a skill rooted in her dojo upbringing. Like her fellow operatives, she consumes Spyce, a special spice granting temporary superhuman strength, speed, and agility. Her tactical acumen extends beyond direct combat, excelling in mission planning and deducing enemy objectives from minimal clues.

Yuki's character arc centers on her evolving relationship with Momo. Initially maintaining emotional distance to shield them both, she gradually confronts her fear of attachment. Actions like slapping Momo after a reckless act stem from anger fueled by worry, echoing her unresolved trauma over Nagaho's death. As the narrative progresses, Spyce's effects diminish due to aging, leading to her eventual retirement. In a decisive act to clear Momo's path to leadership, Yuki chooses to erase her own memories of Tsukikage. A post-credit scene, however, hints at lingering echoes of those memories, leaving her ultimate fate ambiguous.