A combat specialist and one of the madmen belonging to the Amou-gumi. He uses a customized gas burner as his weapon. Known by the alias "Gas Burner Nagase," he roasts his enemies to death with flames reaching 1000°C. Having been taken in by the Amou-gumi at the age of 14 and training there ever since, he is also called the "Child of the Amou-gumi." His primary duties include protecting Kyoko Amou, a key figure in the family and his adoptive mother, and auditing paperwork. When not on guard duty, he participates in raids. He is 181cm tall with blood type A. Since he had already been training for over 20 years after being taken in at 14, he is estimated to be in his mid-30s, likely in the same generation as Kenshin Muguruma of the Kyogoku-gumi (who is 35). While a past organization chart placed him between Kohei Nagumo and Soichiro Wanaka, it has since been confirmed that he and Wanaka started at the same time. True to the reputation of the Amou-gumi's combatants, he is a madman with a sadistic streak, cackling as he burns people alive. He loves the smell of burning human flesh, claiming it's enough to make him eat six bowls of rice. He is deranged enough to assert that the sound of humans burning has a healing effect. During combat, he uses lines reminiscent of a chef—specifically a sushi chef—threatening to sear his enemies into "fatty salmon."

Namu Amida Butsu... Namu Amida Butsu... I'm gonna live a happy life until I'm a geezer! A combat specialist for the Amou-gumi. One of the "madman brothers" that Kotoge fears, he is a master swordsman who wields a katana with peerless skill. Known in the underworld as "Wanaka of the Katana," he is a terrifying expert capable of slicing opponents into rings, limbless trunks, or clean halves with incredible power and speed. His combat ability is considered top-tier within the organization, rivaling that of Koushin Kobayashi.

A combatant for the Mad Cartel. A young man wearing a demonic gas mask and grey camouflage gear. His alias is "Faceless Lewis." He wields a mace that resembles a demon's weapon. Though he speaks and thinks in a childish manner, his combat prowess is extremely high. His gas mask was shattered during a fight with Suwa, but he apparently keeps many spares. He was defeated by Suwa in their second encounter and was on the verge of death, but miraculously survived because his brainstem was protected by cranial implants. However, he is expected to suffer permanent aftereffects. "Brain go BOOM!"

A combatant for the Mad Cartel and a comrade of Lewis. A Polynesian man characterized by orange hair and abnormally developed muscles. His alias is "The Iron Giant." An ultra-aggressive fighter who possesses overwhelming power and toughness, wielding a massive club. He joined the mission to purge the Uragami midway through.