Doppo Kunikida is a core member of the Armed Detective Agency, serving first as a detective before rising to interim director and second-in-command. He possesses a tall, slim build, deep green-grey eyes, and neat golden-blond hair tied in a long ponytail. He consistently wears glasses and his standard attire is a beige vest over a black long-sleeved shirt, a red ribbon bow tie, beige pants, and brown shoes. After the Agency is framed as terrorists, his appearance shifts to a white hood suit and later military riot gear with black boots and gloves. Temporary changes include wearing a prison uniform following wrongful imprisonment and suffering double arm amputations from an explosion; these injuries are later healed through medical intervention. Kunikida's personality centers on strict adherence to a personal code of ideals meticulously documented in his notebook, which he views as an omnipotent guide for life, work, and morality. He exhibits professionalism, diligence, and prioritizes the Agency's reputation above personal concerns. This idealism fuels practical, sometimes ruthless decision-making, like initially advocating abandoning Atsushi Nakajima or discouraging efforts to rescue Kyoka Izumi to avert greater risks. Despite this pragmatism, he deeply values human life and strives to resolve conflicts bloodlessly, especially distressed by harm to Yokohama's youth. His rigid nature includes maintaining detailed daily schedules and listing 58 criteria for an ideal spouse. He exhibits naivety, frequently believing false information from his partner Osamu Dazai—such as health benefits of nooses or shouting-induced hemorrhoids—and recording it in his notebook. He is prone to exasperated outbursts, often triggered by Dazai, though he respects Dazai's strategic intellect and Ranpo Edogawa's deductive abilities, actively participating in maintaining the illusion of Ranpo's supernatural deduction skill. His ability, "The Matchless Poet," materializes objects written in his notebook, provided they fit within its dimensions and he can recall their specifications. He commonly creates non-lethal tools like wire guns, stun grenades, handguns, and keys, reflecting his preference to minimize fatalities. The ability can be activated remotely using pre-written notes, useful when restrained or supporting allies from a distance. Beyond his ability, he is proficient in martial arts trained by Agency president Yukichi Fukuzawa, though he never defeated Fukuzawa in practice. This training enables him to restrain opponents and exhibit enhanced strength, such as tearing through vines. Before joining the Agency, Kunikida worked part-time as an algebra teacher at Shin-Tsuruya Institute, resigning after the Azure Apostle case to devote himself fully to detective work. His backstory reveals he was a college dropout, paralleling the real-life Kunikida's educational struggles. The Azure Apostle case profoundly impacts him; he fails to save multiple kidnapping victims, and subsequent media exposure of this failure, combined with the deaths of informant Rokuzo Taguchi and culprit Nobuko Sasaki—who mirrored his real-life wife—challenges his ideals. This trauma leaves him haunted by unsaved lives, intensifying his internal conflict between idealism and harsh realities. Character development occurs through ongoing ideological challenges. In an OVA episode, he intervenes in a subway bombing, abandoning his strict schedule to save a girl, Aya Koda, and confronts bomber Shōsaku Katsura. Forced to choose between disarming train-track bombs or saving Aya, he opts for the latter, embracing her during the explosion—a decision mitigated only by timely medical intervention, reinforcing his commitment to preventing deaths despite personal cost. During the Hunting Dogs arc, antagonist Saigiku Jōno critiques his ideals as unsustainable, predicting their collapse if comrades died. This confrontation, combined with witnessing more deaths, erodes Kunikida's self-confidence and causes a mental breakdown. He later sacrifices himself in an explosion to protect colleagues, declaring his ideals will endure "with his life as fuel." Despite these struggles, he maintains loyalty to the Agency, especially after reuniting with members to confront adversaries. His leadership potential is acknowledged when Dazai identifies him as the future Agency president.