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Osamu Dazai ( () (ざい) (おさむ), Dazai Osamu?) is a member of the Armed Detective Agency and former executive of the underworld organization, the Port Mafia. He has the Ability named No Longer Human.


Dazai is a young man with mildly wavy, short, dark brown hair and narrow dark brown eyes. His bangs frame his face, while some are gathered at the center of his forehead. He is quite tall and slim in terms of physique.

For his attire, Dazai wears a long sand-colored trench coat, the belt of which he leaves untied. Under it is a black vest over a striped dress shirt that is light blue in hue. He wears a bolo tie, which is held by a brown ribbon and a turquoise pendant. He also dons beige pants, dark brown shoes, and has bandages wrapped around his entire body; only his face, hands, and feet are left uncovered.

Back when he was in the Mafia, Dazai wore a black trench coat that reached under his knees. He also wore bandages over his right eye and his right arm is in a sling—presumably products of his suicidal pastimes. At some point, he was able to regain the use of his right arm.[11]

After the cannibalism, Dazai wears a formal suit during the Agency's celebration.[12]

During the Yokohama fog incident, Dazai wears a white waistcoat over black long sleeves and a brown tie, together with white pants. A lapel pin can be also seen attached to his padded overcoat.[13]

After being arrested by the Hunting Dogs and taken to Meursault, Dazai is currently wearing white prison clothes.[14]



Dazai is a mysterious person, his true intentions are never revealed unless he reveals them. The person who got closest to the truth of his personality, as acknowledged by Dazai himself, was his friend Sakunosuke Oda, who recognized that Dazai shall linger in the darkness forever, as there was nearly nothing that can surpass his mind. Regardless whether he is on the side of killing people or saving them, Oda knew that no place in the world could fill Dazai's loneliness, which Oda thought Dazai knew in himself.[11]

Dazai as the youngest executive

Dazai as the youngest executive in Mafia history.

In addition, Dazai kept an enigmatic and dark façade, whose endeavors in the Mafia were unrivaled and eventually earned him the status as the youngest leader in the history of the Mafia ( (れき) (だい) (さい) (ねん) (しょう) (かん) (), reki daisainenshō kanbu?).[3] Because of his aptitude despite his youth, Dazai contributed to about half the Mafia's profits for at least two years.[11] Eventually, Dazai's ledger became tainted; Ichiyō Higuchi describes his blood to be "dark as the Mafia itself".[1] Even in his adulthood when he becomes an Agency member, when Kyōka Izumi showed remorse over having killed 35 people, Dazai remarked with a sinister face that such number is nothing.[15]

As a saying in the Mafia went, "The greatest misfortune for Dazai's enemies is that they are Dazai's enemies", for Dazai was aptly described to be "practically born to be in the Mafia". He was extremely confident and was a terrific planner, coming up with long-run strategies to subdue his enemies. For instance, he was able to lure Mimic operatives, who were previously trained soldiers, to fall under his trap.[11] Dazai is quite skilled in persuasion notably through his words, which he appeared to utilize in interrogations that broke targets who did not divulge anything under Kōyō Ozaki's torture squad.[16]

Oda's final moments

Dazai advised by Oda to save others.

Behind this grim persona, Dazai admitted that he joined the Mafia to be exposed to death, violence, and people giving in to their urges and desires, expecting that—in this way—he would be able to see the inner nature of humankind firsthand in hopes of finding a reason to live.[11] Following Oda's demise, Dazai defected from the Mafia and went underground in order to heed Oda's final request for him to "be on the side that saves people". Admittedly, he reckoned that people change over time[1] where potential surfaces,[15] which apparently seems to apply to himself as well.

Upon joining the Agency, Dazai is usually called lazy, with Doppo Kunikida always scolding him for being unproductive and slacking off. Despite that, he has shown a sharp wit, deducing all the unlikely situations that led Atsushi Nakajima to believe he was being stalked by a tiger when he was the tiger in question.[17] He has complete confidence no matter what type of situation he is dealing with, be it combat or simply bad situations he formulated in the first place.[18][3]

Dazai after eating a weird mushroom

Dazai eats a hallucinogenic mushroom.

In most occasions, Dazai is overly dramatic. He takes most of his actions as a joke, and, although they are very well-thought plans, he does not credit himself for most of what he has done. Dazai likes to tease anyone and everyone, especially if it means that he can get a laugh out of it.[3] As a suicide maniac, he often attempts to commit suicide in comical manners, but he oftentimes fails[6] or gives up on it when such methods are painful.[10]

Dazai proposes to the woman

Dazai's typical approach to invite a woman in to join him in a double suicide.

Dazai, in particular, wishes to commit double suicide with a beautiful woman;[19][20][3] though he admits that he "likes all types of women", he possibly prefers the type who would die with him if he asked to.[11] Kunikida once wondered why Dazai is quite popular with women and called him a menace to women,[21] a sentiment Chūya Nakahara once used when he threatened to leak Dazai's address to every woman he ever made cry, which Dazai soon asked him not to do.[2] Dazai also once had a run-in with a bomb threat instigated by a woman whom Dazai figured was obsessed with him.[21]

While his suicidal tendencies are initially comedic, they reveal a truly dark deep hole that Dazai has. Even as a teenage boy, Dazai questioned whether there was any value in life.[9] Thus, he soon tried to fill this hole and find a reason worth living for, choosing to live a life surrounded by bloodshed and war, but his friend Oda with his dying breath convinced him to choose the good side. He understood that even though good and evil mean little to Dazai, he may become a slightly better person if he were to choose well.

Dazai trains Akutagawa

Dazai training Akutagawa.

In the past, while he was still suicidal, it was shown to be far less comedic. He even described the death as a way to free himself from the oxidizing world, but, strangely enough, he could not die no matter how hard he tried. Additionally, he was extremely brutal and methodical, setting up traps to catch captives alive to torture them for information, and he would often beat his then apprentice Ryūnosuke Akutagawa for disobeying orders and to push him to the limits to improve his abilities.[11]

ODEE Kunikida pointing a gun at Dazai

Dazai allows suspicions to surround and frame him in order to outmaneuver the Azure Apostle.

While in the present he is more lighthearted and comical, he still retains some of his darker personality. He is still able and proficient at coming up with long-run strategies, though he doesn't inform his teammates what they are until the time is right.[22] When he is able to see through the enemies' schemes, no matter how complex, Dazai would sometimes plot to run along with a charade if he deems it necessary, which he did during his entrance exam in order to let Kunikida's suspicions arouse over him as planted; in so doing, they were able to break free from their opponent's ruse and eventually catch the mastermind behind.[6]

Dazai is also willing to use dirty means to achieve his goals, such as purposely deflating Ango Sakaguchi's car seat airbag when they crashed so Ango would get injured and force him to cooperate with Dazai for pardoning Kyōka in exchange for having his wounds healed.[23]

Atsushi asking Dazai the reason why his ability to transform was kept as a secret

Dazai advises a conflicted Atsushi.

Nonetheless, he does care for his teammates and watches out for them, especially Atsushi for whom he sees the greatest potential. Moreover, Dazai develops a sense of duty and utilizes his wit and intelligence to the Agency in their quest to help maintain Yokohama's peace and order. As part of his various plans and well-calculated strategies, he even devised for Atsushi and Akutagawa to collaborate at times to become a new generation of Twin Dark who could take on the brewing evil lurking within the city.[24]


Main article: No Longer Human

No Longer Human ( (にん) (げん) (しっ) (かく), Ningen Shikkaku?) allows Dazai to nullify others' abilities on contact. It relies on skin contact and is always active. As such, he can nullify any ability even while restrained as soon as it touches him.

No Longer Human ( (にん) (げん) (しっ) (かく), Ningen Shikkaku?)
No Longer Human Manga Debut: Chapter 1
Anime Debut: Episode 1
Ability: Ability Nullification


  • Intelligence: Dazai's intelligence is his primary source of expertise as a Mafia executive in the past and as a detective at present. Ōgai Mori, a proficient tactician himself, widely trusted and relied on Dazai's intelligence, whom he claimed to be his most worthy right-hand man should he have stayed in the Mafia.[25] Dazai is also recognized as one of the Agency's sharpest detectives (双璧, Sōheki?, lit. "Double Jade") together with Ranpo,[4] who is proclaimed by others and himself as the world's greatest detective. With his intelligence, he is able to go head-to-head against the formidable Fyodor Dostoevsky, an avatar of cunning who sees Dazai to be quite identical to him.[26] Even Ranpo once subtly admitted that going up against Fyodor is like going up against Dazai,[27] whom the great detective himself views to be quite an enigma even as his co-worker.[20] Dazai has an aptitude for predicting outcomes,[22][24] which he himself admits is one of his strong qualities, if not his strongest.[3][2]
    • Negotiation Skills: Dazai is an adept persuader, able to negotiate with others and consequently acquire his required outcomes. He is able to convince Kōyō, a Mafia executive, into letting Kyōka get arrested and even to stay in the Agency as their captive;[28][24] Francis Scott Key Fitzgerald, a former enemy, into collaborating with him to catch Fyodor;[12] and even Akutagawa into tailing and potentially helping Atsushi—the latter's sworn rival—before the outbreak of the Decay of the Angel' terrorism plot.[29] He also once presumably persuaded Naomi Tanizaki to work with him behind her brother's back, who both were secretly tasked by Kunikida into tricking Dazai, only for this scheme to backfire once Dazai realizes their clandestine arrangement.[21]
  • Dexterity: Dazai is proficient in lock picking, such as prying locked boxes[11] or handcuffs[18][13] open. Moreover, he was able to implant a bug in Higuchi's pocket without being noticed by the mafioso.[30] He was also able to swipe Chūya Nakahara's knife without even being seen.[2] Kunikida also once described Dazai to be "frighteningly dexterous", knowing that Dazai can pick a lock to a bank's safe with a needle or easily switch out slips of paper with fake ones.[21]
  • Physical Prowess: Dazai had fair-to-middling hand-to-hand skills among the Mafia as Chūya recalled, which his nullification ability made up for. Dazai was able to briefly hold his own against Chūya, the most physically gifted in the Mafia, by predicting and defending against his moves and timing which he had memorized, though he got backed up on the wall soon after.[3] Dazai was also able to fend against a big man by utilizing his resources around him, albeit being overwhelmed later on.[6]
  • Heart Rate Manipulation: Using the device that monitors his vitals which is planted on him at Meursault, Dazai can vary his heart rate at will and digitize his messages in order to communicate to the outside world.[31]


During his time as a Mafia executive, Dazai held a record of 138 counts of conspiracy to murder, 312 counts of extortion, and 625 counts of assorted fraud, among other crimes.[32] After he defected from the Mafia and went underground, this ledger was wiped clean by the Seventh Agency, who were employed by Ango.[28][33]


Main article: List of Battles
Fifteen Arc
Azure Apostle Arc
Osamu Dazai vs. Big Man Osamu Dazai vs. Big Man Unsettled (Changed opponents)
Port Mafia Arc
The Guild Arc
The Guild Aftermath Arc


Manga Appearances
Chapters in order of appearance

Port Mafia Arc

The Guild Arc

The Guild Aftermath Arc

Cannibalism Arc

Perfect Crime Arc

Hunting Dogs Arc

Sky Casino Arc

Kamui Revelation Arc

Vampire Infection Outbreak Arc

Anime Appearances
Episodes in order of appearance

Port Mafia Arc

Azure Apostle Arc

Dark Era Arc

The Guild Arc

Fifteen Arc

The Guild Aftermath Arc

Cannibalism Arc

Perfect Crime Arc

Hunting Dogs Arc

Anime Appearances
Episodes in order of appearance


  • (To Sakunosuke Oda) "For most things in life, it's harder to succeed than fail. Wouldn't you agree? […] That's why I should attempt suicide rather than commit it! Committing suicide is difficult, but it should be relatively easier to fail at attempting suicide!"[11]
  • (To Sakunosuke Oda when asked how he got his injuries) "I was walking and reading a book called How to Not Get Hurt Out of the Blue and fell into a drainage ditch. […] I was speeding around a mountain path and drove off the cliff. […] I was trying to kill myself by slamming my head into the corner of a block of tofu."[11]
  • (To Ango Sakaguchi and Sakunosuke Oda) "Who wouldn't want to keep a relationship's fire burning? Sounds wonderful if you ask me."[11]
  • (To Ango Sakaguchi and Sakunosuke Oda) "I always lose the things I don't want to lose the most. That's why I don't feel anything anymore. The moment you get your hands on something worth going after, you lose it. That's just how things are. There is nothing worth pursuing at the cost of prolonging a life of suffering."[11]
  • (To Sakunosuke Oda) "Hey, Odasaku, do you know why I joined the Mafia? I joined the Mafia because of an expectation I had. I thought if I was close to death and violence—close to people giving in to their urges and desires, then I would be able to see the inner nature of humankind up close. I thought if I did that… I would be able to find something—a reason to live."[11]
  • (To Sakunosuke Oda) "You're such an idiot, Odasaku. The biggest idiot I know. […] You didn't have to do this. You didn't have to die."[11]
  • (To Ōgai Mori) "You were afraid, weren't you, Mori-san? Afraid I'd cut out your windpipe and assume the boss' seat. Just as you did to the last boss."[25]
  • (To Fyodor Dostoevsky) "You said that we were two peas in a pod. You're right, but there's one key difference. ……It's true that all of mankind is sinful and foolish. But what's wrong with that?"[26]
  • (To Fyodor Dostoevsky) "You don't really understand God one bit, do you? 'Perfection and harmony'? God doesn't give a single care about those. I've seen it so many times… His gimmicks are the accidental and the illogical. That's… a weakness you and I both have. We thought of thousands of ingenious schemes, and we still ended up in here… in a prison at the ends of the earth. The ones who actually make the world turn… are those who scream within the storm of uncertainty and run with flowing blood."[34]


  • The name "Osamu" (治) is a given name.[35]
  • The surname "Dazai" means "thick" (太) (ta/da) and "rule" (宰) (zai).


Main article: Real-life References#Osamu Dazai
Osamu Dazai (June 19, 1909– June 13, 1948)
DazaiRL Thumbnail
A brilliant writer who attempted suicide multiple times (before succeeding on his third try), Dazai is one of the most notable writers of "I-novels - first person, semi-autobiographical works emphasizing darkness of the self. His most famous novel, "No Longer Human" follows a man who goes through life feeling as if he is merely "acting" the part of a human."[36]


  • According to 1st official guidebook:[37]
    • What are you strengths and weaknesses? "I only have strengths."
    • Who is your ideal partner? "Someone who I can commit suicide with."
    • What do you want now? "Sake."
    • What is your motto? "A clean, bright and cheerful suicide."
    • The most you’ve ever thought you were going to die "Never."
  • According to 2nd official guidebook:[7]
    • How do you spend your free time? "Nothing."
    • What time do you sleep and wake up? "Irregular, but I don't sleep much."
    • How do you feel about teaming up with Chūya again? "Thinking of new ways to annoy him if by some chance I have no choice but to team up with him again."
  • In regards to suicide methods, Dazai have tried the following:
    • Slamming his head into the corner of a block of tofu[11]
    • Death by Poisoning: Mushrooms[6]
    • Asphyxiation[17]
    • Compressed death in a drum[10]
    • Cardiac arrest[4]
  • Dazai is very bad at driving.[6]
  • Dazai seems to be unable to sleep if it is not completely dark.[38]


  1. 1.0 1.1 1.2 Bungo Stray Dogs Manga: Chapter 25.
  2. 2.0 2.1 2.2 2.3 Bungo Stray Dogs Manga: Chapter 31.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Bungo Stray Dogs Manga: Chapter 11.
  4. 4.0 4.1 4.2 Bungo Stray Dogs: 55 Minutes.
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Bungo Stray Dogs Manga: Volume 2.
  6. 6.0 6.1 6.2 6.3 6.4 6.5 Bungo Stray Dogs: Osamu Dazai's Entrance Exam.
  7. 7.0 7.1 7.2 7.3 Bungo Stray Dogs Official Guidebook Shinkaroku.
  8. Bungo Stray Dogs: DEAD APPLE (Film).
  9. 9.0 9.1 9.2 Bungo Stray Dogs: Dazai, Chūya, Age Fifteen.
  10. 10.0 10.1 10.2 Bungo Stray Dogs Manga: Chapter 2.
  11. 11.00 11.01 11.02 11.03 11.04 11.05 11.06 11.07 11.08 11.09 11.10 11.11 11.12 11.13 11.14 Bungo Stray Dogs: Osamu Dazai and the Dark Era.
  12. 12.0 12.1 Bungo Stray Dogs Manga: Chapter 53.
  13. 13.0 13.1 Bungo Stray Dogs: DEAD APPLE (Film).
  14. Bungo Stray Dogs Manga: Chapter 63.
  15. 15.0 15.1 Bungo Stray Dogs Manga: Chapter 35.
  16. Bungo Stray Dogs Manga: Chapter 19.
  17. 17.0 17.1 Bungo Stray Dogs Manga: Chapter 1.
  18. 18.0 18.1 Bungo Stray Dogs Manga: Chapter 10.
  19. Bungo Stray Dogs Manga: Chapter 3.
  20. 20.0 20.1 Bungo Stray Dogs Manga: Chapter 6.
  21. 21.0 21.1 21.2 21.3 Bungo Stray Dogs: The Untold Origins of the Detective Agency.
  22. 22.0 22.1 Bungo Stray Dogs Manga: Chapter 36.
  23. Bungo Stray Dogs Manga: Chapter 33.
  24. 24.0 24.1 24.2 Bungo Stray Dogs Manga: Chapter 37.
  25. 25.0 25.1 Bungo Stray Dogs Manga: Chapter 30.
  26. 26.0 26.1 Bungo Stray Dogs Manga: Chapter 46.
  27. Bungo Stray Dogs Manga: Chapter 47.
  28. 28.0 28.1 Bungo Stray Dogs Manga: Chapter 26.
  29. Bungo Stray Dogs Manga: Chapter 84.
  30. Bungo Stray Dogs Manga: Chapter 4.
  31. Bungo Stray Dogs Manga: Chapter 70.
  32. Bungo Stray Dogs Manga: Chapter 57.
  33. Bungo Stray Dogs Manga: Chapter 70.
  34. Bungo Stray Dogs Manga: Chapter 77.
  35. . Wikitionary
  36. Bungo Stray Dogs Manga: Volume 3, Author Guide.
  37. Bungo Stray Dogs Official Guidebook Kaikaroku.
  38. Bungo Stray Dogs Drama CD: Welcome to Hot Springs.

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