A combat specialist of the Amau-gumi. One of the 'Madman Seniors' that Kotouge fears, he is a master knife wielder known by the alias 'Kobayashi of the Army Knife.' Recently, he has frequently used the masterwork dagger 'Shiran' which he acquired through certain circumstances. He is an expert not only in hand-to-hand combat but also in quick-drawing handguns and handling all sorts of weapons (including improvised items found on the battlefield). His combat ability is said to be top-tier within the organization, rivaling the katana master Wachu. Due to his incredible combat sense and boyish, whimsical behavior, he is often called the number one madman of the Amau-gumi. Even Kotouge, who has survived many battles and grown accustomed to the underworld, still tenses up in his presence. Along with Soichiro Wachu and Hajime Noda, he is officially designated as one of the 'Three Great Seniors,' and including Hisaya Sunaga, they are collectively known as the 'Madman Senior Big 4.' He has a somewhat androgynous appearance with long eyelashes, pale skin, and thick eyebrows, but he usually wears a crazed smile with his eyelids and the corners of his mouth pulled tight. With his dilated pupils and dark circles under his sanpaku eyes, he exudes an eerie and dangerous aura. He wears his light purple hair in a slicked-back undercut. The way he cheerfully hums the Japanese lyrics to the American song 'Green, Green' (though sometimes it sounds like a different song entirely) is, to put it mildly, the mark of a serial killer.

A friendly and charming young member who joined the Amau-gumi because he had no family. He is constantly terrified, his legs shaking at the brutal scenes of the underworld. He recently grew a backbone after being severely disciplined by Senior Kobayashi. He is deathly afraid of Kobayashi. He addresses Kobayashi as 'Kobayashi-no-aniki' (Senior Kobayashi) and always uses polite language.

"If you lay a hand on my beloved Boss, I won't forgive you." A combat member of the Yokohama-based yakuza organization 'Kamishiro-gumi.' He serves as a direct bodyguard for the head of the Kamishiro-gumi, Yoshinobu Kamishiro. While he uses polite language with Kamishiro and Rintaro Ichiai, he speaks casually with Naoji Aki, suggesting they are of equal rank within the group. Since Aki is lower in rank than Ichiai, Aoi Nagato, and Taisei Hirose, it is assumed that Momota, like Aki, is among the lower-ranking combat members. He is a massive man characterized by a dark olive mohawk fade. He wears a black mesh T-shirt, camouflage pants, and black fingerless gloves. Because he is drawn a head taller than other Kamishiro-gumi members, he was thought to be nearly 2 meters tall, but his height was later revealed to be 188cm. His weight is 115kg; though drawn muscular, he has a somewhat heavy build. He always has a sleepy expression and speaks in a somewhat childlike manner. While he doesn't seem to be the sharpest tool in the shed, his loyalty to Kamishiro is profound, befitting a direct bodyguard. He apparently loves meat buns and his Boss.

The Boss of the Yokohama-based yakuza organization 'Kamishiro-gumi.'