Naki is a ghoul originally from the 13th Ward, classified as an S-rated ghoul with a Koukaku kagune type. He was imprisoned in the CCG’s Cochlea detention facility and later liberated during the Aogiri Tree invasion because of his direct association with Yamori, whom he considered his leader and older brother figure. Naki’s personality is marked by childlike innocence, emotional vulnerability, and unwavering loyalty. He is impulsive, easily irritated, and often naive, but also deeply sincere and trusting. He openly boasts about his strength and his position as Yamori’s right-hand man, and he has a habit of cracking his middle finger, mimicking Yamori’s mannerism. His primary motivation is to avoid the intense loneliness he felt after learning of Yamori’s death while still imprisoned; this fear drives him to protect his comrades at any cost, believing that a painful death is preferable to being left alone.

In the story of Tokyo Ghoul √A, Naki appears primarily as a supporting member of Aogiri Tree, often accompanied by the twin ghouls Gagi and Guge. His role expands in the later arcs, where he evolves from a devoted follower into a more responsible leader. His key relationships include his deep reverence for Yamori, his initial hostility toward Ken Kaneki for killing Yamori, and his eventual acceptance of Kaneki as a new figure to follow after recognizing Yamori’s kagune within him. He also forms bonds with other Aogiri members such as Ayato Kirishima and Miza Kusakari, the latter of whom later becomes his partner. Naki’s development shows him gradually learning to balance his emotional impulsiveness with a sense of duty, ultimately taking on the role of protector for his remaining allies. His notable abilities include his Koukaku kagune, which he can use as a form of armor or weapon in combat, combined with a straightforward, brute-force fighting style fueled by his emotional determination.