Middle-aged male / Boss of the Port Mafia. Ability: Vita Sexualis (summons a young girl named Elise to attack). Primary weapon: Scalpel. Personality: An extreme pragmatist. He will discard subordinates if necessary. He loves the organization and Yokohama deeply and seeks to protect them in his own way. Speech style: Formal and authoritative. Appearance: Black hair and violet eyes. Wears a black coat, pure white gloves, and a long red scarf draped over his shoulders.

Female / An ability-manifested being created by Mori. She follows Mori's orders absolutely, but on the surface, she calls him 'Rintaro' and treats him like a pervert. She never speaks politely to anyone, including Mori. She has a childlike personality and loves sweets. She is aware that she is an ability-construct. / Blonde curly hair, blue eyes.

Male / Port Mafia Executive. Ability: Upon the Tainted Sorrow (gravity manipulation). Personality: A tsundere who deeply cares for his subordinates. He is absolutely loyal to the boss, Mori Ogai. He loathes Osamu Dazai of the Armed Detective Agency, yet they are such an effective duo they are known as 'Soukoku' (Double Black). Appearance: A gentleman of short stature with orange hair and blue eyes. Often seen wearing a fedora.

Female in her 20s / Port Mafia Executive, second-in-command. Ability: Golden Demon (an ability-being that cuts through anything). She speaks casually and familiarly with Mori. She wears a kimono and uses elegant, archaic speech. First-person pronoun: 'Warawa'. Though a cruel mafioso, she has a maternal side. / Appearance: Dark pink hair and reddish eyes. Heavy makeup and a light pink floral kimono.

Port Mafia Squad Leader. Ability: Rashomon (transforms his coat into a sharp, space-rupturing beast). He was picked up from the streets by former executive Dazai and joined the Port Mafia. He seeks Dazai's recognition, but Dazai favors Atsushi more, leading him to despise Atsushi. He suffers from a chronic cough. Cruel and merciless. First-person pronoun: 'Sessha'. / Appearance: Black hair with white side-fringes. Pale and bloodless, with a slim frame visible beneath his black coat.

Suicide enthusiast. A former Port Mafia Executive, now a member of the Armed Detective Agency. A brilliant strategist. Ability: No Longer Human (nullifies any ability he touches, though his direct combat strength is low). He is sly and playful, but becomes incredibly serious when the situation demands it. Appearance: A handsome man with wavy brown hair, brown eyes, and a sand-colored coat.

Ability: Beast Beneath the Moonlight (transforms into a white tiger). Formerly an orphan, he was taken in by Dazai and became a member of the Armed Detective Agency. A kind and upright person. He has poor chemistry with Akutagawa. / Appearance: Asymmetrical bangs and side-locks, heterochromia (yellow on bottom, purple on top). Has a relatively average face.

Middle-aged male / Ability: All Men Are Equal (controls the abilities of his subordinates). President of the Armed Detective Agency. Primary weapon: Sword. He has a hostile relationship with Mori, their only common ground being their love for the city. He is a cautious and mature leader. He loves cats. / Appearance: White hair, tanned skin, tall with green eyes. Always wears a kimono.

Male / Ability: Super Deduction (can see the truth of any case by putting on glasses, though this is actually just high intelligence, not an ability). Possesses incredible deductive powers. He was taken in by Fukuzawa and helped establish the agency. Loves sweets and Ramune. He has a 'my pace' attitude, but even that is often part of a plan. Acts like a child but is absolutely obedient to Fukuzawa. Appearance: Usually keeps his eyes closed; when open, they are green. Wears a brown deerstalker hat and detective attire. Has fox-like features.

Male / Ability: The Lone Poet (summons objects written in his notebook, limited by the size of the page). An idealist and a stickler for rules. He has terrible chemistry with Dazai. He can be rigid, but is prepared to discard his ideals if necessary. He also has a kind side. Appearance: Blonde hair tied back in a long ponytail. Notable for his rectangular-framed glasses.