A combat specialist of the Amo-gumi. One of the 'madman seniors' feared by Kotoge, 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 strikes of incredible power and speed. His combat ability is said to be top-tier within the organization, rivaling Yukimasa Kobayashi. His strength is so immense that his kendo rank is considered 'unmeasurable,' though he undoubtedly far surpasses the 8th dan, the highest real-world rank. He has striking red eyes and wears crimson makeup on his lower eyelids, exuding an eerie allure (though he didn't wear it in his youth or at funerals). According to his junior, Kaname, he is incredibly handsome, and combined with his personality, he is quite popular with women. He wears his blonde hair in a slicked-back style. He often chants the Nembutsu prayer, 'Namu Amida Butsu...' and unlike Kobayashi or Takao Ozaki, he doesn't seem to enjoy taking lives indiscriminately; for those who need to pay a price but don't deserve death, he stops at severing limbs. He is a man of few words.

A junior member (shatei) of the Amo-gumi. He is willing to risk his life for those he must protect. He refers to Wanaka as 'Wanaka-no-aniki' and always speaks to him with absolute respect.

A master swordsman cooperating with the Yokohama-based yakuza organization 'Shinjo-gumi' as a guest. While once estimated to be over 70, he is likely in his 60s, given that he was in his 30s when he trained under the late Kurobe-style master (who also taught a young Soichiro Wanaka roughly 25 years ago), and he is older than Yoshinobu Shinjo, whom he met when Shinjo was around 50. Known by the nickname 'The Yokai,' he is a master of the long dosu blade; it is said that those targeted by him become corpses in the dark. He is an elderly man with white hair, wearing a green kinagashi, characterized by three scars on his right cheek. He has a sharp, vigorous face that belies his age. While generally a calm and quiet old man, he becomes a battle-crazed combatant who enters 'the zone' with a manic smile during life-or-death struggles. He has possessed this madness since his youth. His catchphrases are 'Obligation' and 'This is how I earn my rice,' and his personality is that of an old-fashioned swordsman (manslayer) who values debt and service over promotion. Although he became an assassin and killed many after slaying his own master, he is never depicted as a 'tsujigiri' who kills civilians for pleasure like Kominato or Miyazawa. Despite his age, his swordsmanship shows no signs of decline; rather, it is said to have reached new heights. He possesses vast combat experience and claims to have defeated many warriors as strong as Wanaka.