The deuteragonist of the manga Sakamoto Days. A killer with the psychic ability to read minds. He originally came to persuade Taro Sakamoto, who had retired to run a store, but was instead moved by seeing Sakamoto fight to protect his family's daily life, leading him to become a colleague working at the store. He generally has an amicable personality and gets along well with others, though they bicker occasionally. However, his true nature is rougher than it appears. He follows a no-kill policy in accordance with Sakamoto's wishes. His intelligence is at an ambiguous level—not bad, but not particularly high. He has good comprehension and can understand most explanations, and his creativity allows him to come up with brilliant ideas during combat. However, because he spent his life fighting without a proper education, his intellectual level isn't high, which sometimes earns him rebukes. His shortcomings become clear when he speaks with intellectual characters like Lu Shaotang, Natsuki Seba, or Amane Yotsumura. He is the object of Guest's unrequited love.

A psychic fortune-teller hired by the JAA boasting a 100% accuracy rate, known as the JAA's strongest diviner. She has a selfish personality and tends to push people around, but she also has a kind side, helping those around her with her divinations without question. She is currently in a flirtatious relationship with Shin Asakura.

One of the killers belonging to ORDER, the JAA's direct special duty unit. He has a deep connection with Taro Sakamoto, having been classmates since their time at the JCC, the assassin training school. He appears to have a very sly and playful personality, which he shows to allies and enemies alike. He seems to get along with the eccentric Osaragi, though he often draws her ire. While he seems inscrutable, he is actually one of the most deeply caring characters in the series. His strong sense of camaraderie is often revealed, such as when he mourns fallen comrades with a lonely expression, warns Sakamoto about a bounty on his head, or tries to uncover the truth behind the death of Rion Akao, who was long thought to be dead. He is currently harboring an unrequited love for Guest.