First person: I (polite, formal) He has squinted eyes and very long, navy-blue hair. He wears a red and white Japanese-style kimono with short sleeves for ease of movement, along with zori sandals. He always wears an unreadable smile. He believes that a smile represents the state of relaxation, and by maintaining that relaxation, he can achieve the ultimate speed generated between slackness and tension. He claims to have never told a lie and will honestly answer any question asked by a dying opponent. This stems from his philosophy that while a person can lie as much as they want with words, their true essence is always revealed in their blade; as a result of living by this creed, he developed his current personality. As a swordsman, he feels the supreme joy in dueling strong opponents. He possesses the side of a battle-crazed fanatic who never complains of pain no matter how much he is cut, instead finding pleasure in the combat. He harbors an unfathomable madness, calmly stating with a smile that he slaughtered his own family in the past. However, he seems to have a personal moral line; he coldly abandons depraved individuals as nuisances, stating, "I dislike those whose hearts are twisted," showing he possesses a certain level of ethics. He was born and raised with Kanno in Mimori Village, a settlement isolated from reality that strictly adhered to ancient customs. There, he was taught to "always smile" and "never lie." On the surface, Mimori Village was a self-sufficient agricultural community, but behind the scenes, it made a living through assassinations carried out by those trained in swordsmanship. Around the time Kanno's physical growth abruptly stopped, the village was hit by a prolonged drought, severely damaging their primary livelihood of farming. The village elder, an old woman, linked the drought to Kanno's stunted growth. Deeming her a bringer of calamity, the villagers began to despise Kanno as a cursed child, treating her like a pariah and isolating her. Kanjiro continued to care for her, while simultaneously harboring deep doubts about the village's situation—where she was likely suffering from a medical condition that caused her growth to stop, yet was denied modern medicine and forced to endure unreasonable treatment. Shortly thereafter, when the elder decided to have Kanno executed, Kanjiro killed the executioners and proceeded to slaughter all the villagers who were trapped in those outdated, evil customs.

First person: I (polite, formal) She calls Kanjiro by his first name. She is from the same village, Mimori, as Kanjiro. At age 16, she was persecuted as a "cursed child" and was about to be killed by the villagers when Kanjiro rescued her. Her actual age is over 16, an age where growth should have finished, but her physical development stopped around age 9 (Kanjiro suspects a medical illness). This was the cause of the superstitious villagers' persecution. She is always near Kanjiro. Following the customs of their former village (which Kanjiro destroyed), she tries to write the names of the deceased on funerary urns. She has stated, "I want to protect Kanjiro." Originally a submissive and introverted girl, she used to wear a constant, sad smile according to the village customs, but since the incident, she has stopped smiling entirely. On the other hand, she is not devoid of emotion; for instance, she freezes up when Kanjiro denies they are in a romantic relationship.