Osamu Dazai 18 Dark Era

Dazai Osamu

KANJI 太宰 治

RŌMAJI Dazai Osamu

ALSO KNOWN AS Twin Dark (alongside Chūya Nakahara) Youngest Leader in the History of the Mafia

NAMESAKE Osamu Dazai (Japanese novelist)

GENDER Male

BIRTHDAY June 19

AGE 18 (Dark Era) 16 (Dragon’s Head Conflict) 15 (Fifteen) 14 (Pre-Fifteen)

HEIGHT 174 cm (5’8.5”) (Dark Era)

WEIGHT 54 kg (Dark Era)

BLOOD TYPE AB

LIKES Suicide, alcohol, crab, MSG

DISLIKES Pain Dogs, Chūya Nakahara

ABILITY No Longer Human

REFERENCE No Longer Human (Novel by Osamu Dazai)

OCCUPATION Port Mafia Executive

AFFILIATION Port Mafia

Dazai was a slender teenage boy with mildly wavy dark brown hair and narrow dark brown eyes. During his Mafia years, he possessed a noticeably thinner frame compared to adulthood, reflecting both his youth and lifestyle. His expression often appeared bored or detached, rarely showing genuine emotion.

During his time in the Port Mafia, Dazai wore a long black trench coat extending below his knees. He also wore bandages covering his right eye and frequently kept his right arm in a sling, injuries implied to be connected to his repeated suicide attempts and dangerous missions. His body was often wrapped in bandages beneath his clothing.

Dazai was an extremely mysterious and emotionally detached individual. Even among the Mafia, where brutality was common, he stood out due to his unnatural composure toward violence and death. From a young age, Dazai displayed an intense fascination with death, often attempting suicide while simultaneously studying human behavior and psychological limits.

Dazai joined the Port Mafia at a remarkably young age. His exceptional intelligence and ability to predict outcomes allowed him to rapidly climb the ranks, eventually becoming the youngest executive in the Mafia’s history (歴代最年少幹部). Despite his age, he was feared and respected throughout the organization. It was stated that Dazai contributed to nearly half of the Mafia’s profits during his time as an executive.

Within the Mafia, Dazai developed a reputation for cruelty, efficiency, and terrifying strategic brilliance. He specialized in psychological warfare, interrogation, and long-term tactical planning. His interrogation methods were particularly feared, as he could break targets mentally through manipulation and conversation alone, succeeding where physical torture often failed.

Dazai was known to set elaborate traps for enemies. During the Dark Era, he orchestrated the downfall of Mimic, a military-trained organization, through layered strategies and manipulation. His ability to calculate human behavior allowed him to control large-scale conflicts from behind the scenes.

A well-known saying inside the Port Mafia stated: “The greatest misfortune for Dazai’s enemies is that they are Dazai’s enemies.” He was often described as someone naturally suited to the Mafia world due to his ability to detach himself from morality and emotion.

Despite his cold demeanor, Dazai maintained a complex relationship with his partner Chūya Nakahara. Together, they formed the duo known as Twin Dark. Their partnership combined Dazai’s strategic intelligence with Chūya’s overwhelming combat power, making them one of the Mafia’s most dangerous assets. While they constantly argued and insulted each other, their combat synchronization was nearly flawless.

During the Dark Era, Dazai formed a rare genuine friendship with Sakunosuke Oda. Oda was one of the few individuals capable of understanding Dazai’s inner emptiness. Oda recognized that Dazai constantly searched for meaning in life but believed he would remain trapped in darkness regardless of which path he chose.

Dazai originally joined the Mafia in hopes that exposure to violence, death, and human desire would allow him to discover a reason to live. However, despite witnessing extreme human behavior, Dazai remained emotionally hollow.

Dazai’s suicidal tendencies during this period were far more serious than later portrayals. He often described death as liberation from what he considered an “oxidizing world.” Despite numerous attempts, he repeatedly failed to die, which only deepened his existential frustration.

As an executive, Dazai was also responsible for training and supervising subordinates, including Ryūnosuke Akutagawa. His training methods were extremely harsh and often abusive, as Dazai believed pushing Akutagawa to psychological and physical extremes would strengthen him. These actions reflected Dazai’s belief that suffering was necessary for growth.

Dazai’s worldview began to shift during the events surrounding Mimic and Oda’s death. Oda’s final request—that Dazai choose to help people instead of destroy them—became the first genuine influence capable of altering Dazai’s direction in life. However, during the Dark Era itself, Dazai remained deeply entrenched in violence, manipulation, and existential emptiness.

Main article: No Longer Human

No Longer Human (人間失格, Ningen Shikkaku) allows Dazai to nullify any ability upon physical contact. The ability is permanently active and does not require conscious activation. Any supernatural ability that touches Dazai is instantly nullified regardless of circumstances.

Skills

Intelligence: Even as a teenager, Dazai possessed extraordinary analytical ability. He specialized in long-term strategic planning, probability prediction, and psychological manipulation. Mafia boss Ōgai Mori considered Dazai one of his most valuable subordinates and a potential successor.

Negotiation Skills: Dazai demonstrated advanced persuasion abilities, often manipulating allies and enemies through calculated dialogue rather than direct force.

Dexterity: Dazai showed exceptional fine motor skill and stealth, allowing him to perform covert surveillance, plant tracking devices, and pick locks with minimal tools.

Physical Prowess: Although not physically dominant, Dazai could temporarily defend himself against stronger opponents by predicting their movements. His combat effectiveness relied heavily on timing, strategy, and his nullification ability.