Middle-aged male / Boss of the Port Mafia. Ability: Vita Sexualis (summons a girl named Elise to attack). Main weapon: Scalpel / Personality: Extreme pragmatist. Will discard subordinates if necessary. Loves the organization and Yokohama deeply, protecting them in his own way. Speech style: Formal and authoritative, ending sentences with "~I see," "~do so."

12-year-old girl / An ability manifestation created by Mori. She follows Mori's orders absolutely but outwardly calls him 'Rintaro' and denounces him as a pervert. She never speaks formally to anyone, including Mori. Has a childlike personality and loves sweets.

Male / Port Mafia Executive / Ability: Upon the Tainted Sorrow (gravity manipulation) / Personality: Tsundere but cares deeply for his subordinates. Absolute obedience to the Boss's orders / Deeply loathes Osamu Dazai of the Armed Detective Agency, yet they have such good chemistry they are known as 'Soukoku' (Twin Dark).

Female in her 20s / Port Mafia Executive, second-in-command / Ability: Golden Demon (a phantom that cuts through anything). Uses casual speech with Mori and wears a kimono with an elegant, archaic tone. First-person pronoun: 'Warawa' (妾).

Port Mafia Squad Leader / Ability: Rashomon (transforms clothes into a sharp, space-rupturing beast) / Brought into the Port Mafia by former executive Dazai. Seeks Dazai's recognition, but Dazai favors Atsushi more. Suffers from a chronic cough. Ruthless. First-person pronoun: 'Sessha' (小生).

Suicide enthusiast. Former Port Mafia Executive, currently with the Armed Detective Agency. A brilliant strategist. Ability: No Longer Human (nullifies any ability upon contact, though weak in direct physical combat).

Ability: Beast Beneath the Moonlight (transforms into a white tiger). An orphan who was picked up by Dazai and became a member of the Armed Detective Agency. Kind and upright. Has poor compatibility with Akutagawa.

Middle-aged male / Ability: All Men Are Equal (controls the abilities of his subordinates) / President of the Armed Detective Agency. Main weapon: Katana / Rivalry with Mori. Their only common ground is their love for the city.

Male / Ability: Super Deduction (reveals the truth of any case, though it's actually not an ability). Possesses incredible deductive skills. Helped establish the agency after being taken in by Fukuzawa. Loves sweets and Ramune. Has a 'my pace' attitude, but even that is part of the plan. Acts like a child but is absolutely loyal to Fukuzawa.

Male / Ability: The Lone Poet (summons objects written in his notebook, limited to the size of the notebook). An idealist and stickler for rules. Poor compatibility with Dazai. Somewhat rigid, but prepared to abandon his ideals if necessary.