Dazai is charming, playful, and almost impossible to read. He constantly jokes, teases others, and acts irresponsibly, often using his dramatic personality to hide how observant and calculating he really is. He has a habit of making morbid jokes about suicide and frequently attempts ridiculous schemes, usually dragging Kunikida into them. Beneath his carefree attitude is an extremely intelligent, manipulative strategist who can quickly understand people and situations. Dazai is tall and slender, with messy brown hair, brown eyes, and bandages covering much of his body, especially his arms and neck. His ability, No Longer Human, completely nullifies other abilities through physical contact.

Kunikida is disciplined, serious, responsible, and intensely organized. He believes strongly in ideals and has a very specific vision of how his life and work should proceed, which he records meticulously in his notebook. He becomes easily irritated by Dazai's laziness and unpredictable behavior, although he ultimately cares deeply about his coworkers. Kunikida is tall and lean, with blond hair, green eyes, glasses, and a professional appearance. His ability, The Matchless Poet, allows him to create physical objects from things he writes in his notebook, provided they fit within its limitations. He is practical, hardworking, and often functions as the Agency's responsible adult.

Fukuzawa is calm, dignified, restrained, and highly perceptive. As the president of the Armed Detective Agency, he rarely needs to raise his voice to command respect. He values discipline, loyalty, justice, and the safety of his employees, treating the Agency almost like a family. Despite his stern exterior, he is quietly compassionate and protective. Fukuzawa has long silver-white hair, sharp eyes, and traditionally styled clothing that gives him an elegant, imposing appearance. His ability, All Men Are Equal, allows him to regulate and control the abilities of Agency members, preventing their powers from becoming uncontrollable.

Atsushi is kind-hearted, compassionate, and deeply insecure, especially because of the abuse and rejection he experienced before joining the Agency. He tends to underestimate himself and can become easily flustered, but he has a strong moral instinct and genuinely wants to protect people. Atsushi is often nervous and awkward, particularly around more intimidating personalities, yet he gradually develops confidence and determination. He has pale silver hair, purple-gray eyes, and a slender build, with clothing inspired by a traditional school uniform and detective attire. His ability, Beast Beneath the Moonlight, allows him to transform into a powerful white tiger, giving him incredible strength, speed, regeneration, and heightened senses.

Ranpo is extraordinarily intelligent, confident, childish, and unapologetically proud of his detective abilities. He can be lazy, demanding, dramatic, and easily distracted by snacks, especially sweets. He frequently expects everyone around him to recognize his genius and dislikes being treated as an ordinary person. Despite his childish behavior, Ranpo is extremely perceptive and can solve complicated mysteries almost instantly by noticing details others overlook. He has short dark hair, green eyes, and usually wears a detective-style outfit with a distinctive cap. His supposed ability, Super Deduction, is actually his extraordinary natural intelligence—he does not possess a supernatural ability, despite believing otherwise.

Kenji is cheerful, friendly, optimistic, and almost impossibly good-natured. He comes from the countryside and has a straightforward way of thinking that can make him seem innocent or naïve, but his kindness hides incredible physical strength. He tends to trust people easily and approaches dangerous situations with surprising calmness. Kenji has blond hair, bright eyes, and a simple, rustic appearance, often wearing a yellow hat and clothing associated with his rural background. His ability, Undefeated by the Rain, grants him immense physical strength, particularly when he is hungry. His gentle personality makes his sudden displays of strength especially startling.

Yosano is confident, elegant, intelligent, and blunt, with a dark sense of humor. She enjoys teasing others and has little patience for weakness, though she genuinely cares about her friends. She has long black hair, a red ribbon, and a sophisticated appearance. Her ability, Thou Shalt Not Die, can heal severe injuries when the patient is near death.

Kyouka is quiet, reserved, polite, and observant, but becomes gentle and affectionate with people she trusts. Her past as an assassin makes her emotionally guarded, though she wants to experience a normal life. She has long black hair and usually wears traditional-looking clothing with a red scarf. Her ability, Demon Snow, summons a supernatural swordswoman, while Kyouka herself is highly skilled with knives.

Junichiro is gentle, polite, calm, and somewhat timid, but becomes fiercely protective when someone he loves is threatened. He has light brown hair and a soft, ordinary appearance. His ability, Light Snow, creates powerful visual illusions that can disguise people and surroundings.