Ritsuka Fujimaru is a Master for the Chaldea Security Organization, resolving Grand Orders to restore the Human Order. An ordinary civilian with no magical training or combat experience, they joined after responding to a station flyer and were accepted on a whim to fill a quota, initially valued as a novice for numbers rather than skill. Physically average, the male version has short black hair and blue eyes; the female version has red hair in a side ponytail. Command Spells appear on their right hand, differing by gender. They utilize various Mystic Codes for missions, including combat uniforms and specialized gear like the Arctic Region Chaldea Uniform and Tropical Summer attire. Neutral Good in alignment, they are described by the Lion King as a soul that "knows good but commits evil, and allows evil while being good." James Moriarty noted they are "good, yet not hating evil, tormented by evil, yet carrying on doing good." They exhibit high empathy and perseverance, forming bonds with Servants by respecting their inherent worth despite conflicting ideologies. A childhood friendship with a WWII veteran neighbor, whose death taught Ritsuka that life holds value even without grand rewards, informs their outlook. Mash Kyrielight regards them as a "senpai"—an ordinary person who strives without giving up, embodying an upright human spirit. Cú Chulainn identifies them as "the most human of all humans" for their resilience and willingness to borrow wisdom to forge a better future. Key relationships include their contract with Mash Kyrielight, whom they comforted during near-death experiences while expressing guilt over burdening her due to their magical inadequacy. Meltryllis valued their unconditional trust when she had nothing to offer. U-Olga Marie recognized their capacity for kindness toward enemies. Quetzalcoatl praised their discipline and earnestness, while Merlin supported them as "the hope of human history." Their development spans critical missions. In the Fuyuki Singularity, they demonstrated composure during crises, a trait noted in later operations. Vlad III commended their tactical prowess after defeat. In the Babylonia Singularity, they investigated the Three Goddess Alliance's threat to Uruk. Across the Epic of Remnant and Cosmos in the Lostbelt chapters, they faced hostile takeovers of Chaldea and navigated alternate histories ("Lostbelts"), making grave sacrifices that tested their moral boundaries as either "a savior or a destroyer." Their resolve was evident during the final battle against ORT in the South American Lostbelt, persisting despite repeated Servant losses.