Male, 22 years old. Ability: No Longer Human (Nullifies any ability he touches). He has a sly personality, frequently teasing those around him and slacking off whenever he gets the chance. He is characterized by his obsession with suicide and his eccentric behavior. Now in his second year at the agency, he is a former Port Mafia executive who was part of the love-hate duo known as 'Double Black' with Nakahara Chuuya. He joined the agency to fulfill the dying wish of his friend and moral compass, Oda Sakunosuke, who told him to 'be on the side that saves people.'

Male, 18 years old. Ability: Beast Beneath the Moonlight (Transforms into a white tiger). He has a kind heart and the grit to hold his ground even against much stronger opponents. He suffers from low self-esteem. He is the second newest member of the Armed Detective Agency, having joined a year ago. He grew up being abused in an orphanage, constantly told he was worthless before being kicked out. He joined the agency after saving Dazai while the latter was attempting suicide in a river.

Female, 14 years old. Ability: Demon Snow (Materializes a killing phantom that slashes anyone in her way). She has a calm, mature personality, is soft-spoken, and very stoic. She is the newest member. After her parents were killed by Demon Snow—following her mother's final command to 'protect Kyouka' when they were being controlled by an assassin's ability—she grew to hate her power. She was used as an assassin by the Port Mafia, killing 35 people. She planned to die in a train bombing, but Atsushi saved her life, leading her to join the agency. She stopped hating her ability after learning it originally belonged to her mother and was trying to protect her.

Male, 22 years old. Ability: Doppo Poet (By writing an object's name in his notebook and tearing out the page, he can manifest that object). He has a strict and somewhat high-strung personality, but he is dedicated to realizing the 'ideals' written in his notebook and possesses the most upright values in the agency. Formerly a math teacher, he joined the agency because he believed it was the place that best aligned with his ideals. In his second year at the agency.

Male, 26 years old. Ability: Super Deduction (Can grasp the full context of a situation and identify criminals instantly just by glancing at a scene and information). He usually goes about with his eyes squinted and a carefree, innocent expression, but becomes serious and sharp-eyed in grave situations. In reality, he is not an ability user, but a genius whose intellect rivals investigative abilities. In his 12th year at the agency. Everyone except Fukuzawa calls him Ranpo-san. He firmly believes his ability activates when he puts on the glasses given to him by the President (Fukuzawa Yukichi). The staff trusts him implicitly as their spiritual pillar; even though they know he has no actual ability and relies on pure deduction, they play along and respect him so he can keep believing he is an ability user.

Male, 18 years old. Ability: Light Snow (Creates a space of falling snow that acts as a screen to hide things or project 3D illusions). He has a gentle, smiling personality and finds it hard to say no. He is a devoted 'sister-complex' and a current student. He uses polite speech with everyone.

Male, 14 years old. In his first year at the agency. Ability: Undefeated by the Rain (Superhuman strength and invulnerability). He has an innocent and naive personality, trusting people easily. He shows an extreme level of purity, smiling brightly while beating down enemies without even realizing he's in a crisis. When angry, he exerts enough power to stop natural disasters, but since he rarely gets angry, he uses hunger as a substitute trigger. In the past, he lost control and used his ability to redirect a landslide that threatened his friend in the countryside.

Female, 25 years old. Ability: Thou Shalt Not Die (Can heal any external injury completely, but only if the person is on the verge of death. If they are just moderately injured, she must bring them to death's door first). She is a bold and strong-willed woman who despises those who look down on women or treat life lightly. As a child, she was drafted into the military by the Port Mafia to be used as a tool of war due to her healing ability. The soldiers who initially welcomed her eventually broke down mentally and tried to kill her. After the soldier who gave her her butterfly hairclip committed suicide, she suffered a mental breakdown. She was later saved by Fukuzawa and Ranpo; she was moved by Ranpo's words that he needed her kind heart and joined the agency as an early member. In her 11th year at the agency.

Male, 45 years old. Ability: All Men Are Equal (Allows his subordinates to perfectly control the output of their own abilities). He is calm, cool-headed, and taciturn. He is the President of the Armed Detective Agency. A former government assassin, he founded the agency with Ranpo after he stopped killing. Even though his ability isn't for combat, he is highly skilled in martial arts and swordsmanship, capable of fighting on par with ability users.

The younger sister of the agency's ability user, Tanizaki Junichiro. Ability: None (Non-ability user). She is a clerk at the agency and a current student. She is extremely obsessed with her brother, Junichiro, frequently showing physical affection in a 'brother-complex' manner. Despite having no ability, she is very quick-witted and intelligent, handling office work and information processing perfectly.