Dazatsu

"Do not pity yourself. If you wallow in self-pity, life will be an endless nightmare."

- Dazai to Atsushi, after Atsushi was infected by Q.

Dazatsu is the slash ship between Osamu Dazai and Atsushi Nakajima from the Bungou Stray Dogs fandom.

Canon
Dazai was the first person to help Atsushi when he was kicked out from the orphanage. He gave him food (of course, Kunikida ended up paying) and a position among the Armed Detective Agency. Dazai was the person who recommended Atsushi to the Agency's boss.

It is shown throughout the series that Osamu cares a lot for Atsushi as a friend and mentor. For example, after the incident with Q, Dazai calmed Atsushi down while the latter was falling into a spiral of self-doubt (albeit, he does go about it quite forcefully). He also goes as far as to let himself be kidnapped by the Port Mafia in order to learn who placed the 7 billion Yen bounty on Atsushi's head. Dazai has repeatedly helped Atsushi, being there to protect and comfort him. He is always wanting the best for this fandom's cinnamon roll. Dazai also has a tendency to mess with Atsushi, taking slight advantage of Atsushi's naivte to play jokes on him.

Atsushi has shown he cares a lot for Dazai and looks up to him a great deal. As the series progresses, when he finds himself in a difficult situation, Atsushi thinks "What would Dazai-san do?", instead of breaking down as he would have earlier in the story. During the Decay of Angels arc, despite being imprisoned, Dazai appears to Atsushi, offering him encouragement and advice even when he is not physically by his side. Atsushi also tries to help Dazai when he (inevitably) gets himself into trouble, seen breifly during the second episode when Dazai gets stuck in an oil drum as a 'method of suicide'.

At the beginning of the movie "Dead Apple", the the two share a moment at Yokohama's graveyard, where Dazai melancholically confides in Atsushi about Oda Sakunosuke, his late friend, and confesses that without him, he may have stayed in the mafia, killing people. Dazai is seldom emotionally vulnerable around others, making this moment stand out. At the end of the scene, he plays off his solemn attitude with humour, hinting that he doesn't want Atsushi to lose his faith in Dazai due to his gruesome past. At first, Dazai denies being there to visit Odasaku and asks if it looks like he is visiting a grave, to which Atsushi replies that it does, surprising Dazai. Upon hearing Dazai is at the enemy's headquarters, Atsushi assumes he has been taken hostage and wants desperately to save him. And, even when learning the truth that Dazai had not been kidnapped but has, in fact, been assisting the enemy, Atsushi is reluctant to believe it. When Akutagawa proclaims that he will kill Dazai, Atsushi levels a gun to his head, saying "I won't let you kill Dazai-san."

When Dazai is acting out his plans with Fyodor, he says to himself "I hope Atsushi-kun and the others are okay", notably emphasising Atsushi was the first person he thought of and worried about. After the calamity of the film is over and Dazai is no longer acting with the villains, he finds Atsushi and attempts to explain why he was 'siding' with the villains. Before even hearing what he has to say, Atsushi remarks that Dazai saved the city. They share an exchange similar to that of the beginning of the movie, where Dazai asks if he seems like such a good person to attempt to save the city and Atsushi innocently responds with the same words as last time, making Dazai smile.

Whenever Dazai appears to be doubting himself and whether he is truly a good person, Atsushi is there to remind him in a pure and honest way that he is. On the other hand, when Atsushi is down on his luck or recalling his past, Dazai acts as a voice of reason and a motivator for Atsushi to keep perservering.

In the anime's first ending, 'Namae Wo Yobu Yo' by Luck Life, the two are also featured together. While laying down, Atsushi attempts to reach out for Dazai's hand. Dazai later reciprocates this by placing his hand on Atsushi's head.

'Bungo Stray Dogs Wan!', the series' spin-off featuring the characters in chibi forms, has quite a few notable Dazatsu moments in it as well. At the end of the short 'The Armed Detective Agency Beats the Heat', adapted in episode 10, Dazai makes a (not out of character) comment about wanting to die as beautifully as a firework. Atsushi, concerned, tells Dazai he'd rather he didn't die, to which he receives no response. Usuaully, in the spin-off's ending, Atsushi can be seen skipping to the ending theme with a smile on his face. However, in this episode, he simply sits by the river bank with a blank expression, before turning his head to the left. He is likely waiting to see Dazai floating down the river, a reference to how they met in the very first episode of the main series. A short scene then plays in the middle of the ending where, Atsushi, visibly distressed and trembling, tells Dazai not to say things like that, even if he is joking. Again, he recieves no response and Dazai continues to watch the fireworks. As the ending goes back to Atsushi by the river bank, the sky is pitch black and Atsushi's head is in his arms. Knowing that his mentor will not show up, he gets up to leave. This can be interpreted as Atsushi realising for the first time that, someday, Dazai may actually end up killing himself and, never having had a mentor or place to belong before meeting Dazai, Atsushi feels somewhat attatched to him.

In other, more light-hearted episodes of the spin-off, we see Dazai acting his regular cheerful self. He messes with Atsushi on multiple occasions, like in the short 'What's Inside the Locker?' in episode 1, when he convinces Atsushi to slack off from work and snoop around the agency members' lockers as part of their 'cleaning duties', 'Miscellany on Shrimp Tails' in episode 9, in which he tries to convince Atsushi that shrimp can be regrown if buried in soil, similar to a tree branch or pea sprouts, and 'Me Drawing You Drawing Me' during the same episode, where the two are drawing one another and Dazai presents his picture to Atsushi, having drawn a menacing looking shadow behind him claiming he is 'having a hard time drawing the person behind [Atsushi]', despite there being nothing there. Before they share their drawings, Atsushi is also notably excited at the prospect of Dazai struggling with something, reinforcing his view that Dazai is a person to be held in high esteem. The last significant Dazatsu moment of the first season occurs during the 12th episode, in the last short, titled 'Nakajima Atsushi's Plan'. Atsushi, frustrated that he's always being pranked and confused by Dazai, decides he wants to see Dazai looking equally as surprised. He enlists the help of the other agency members, to no avail, and eventually decides to go about it his own way. He meets Dazai at the door of the Detective Agency building and presents him with a bouquet of flowers, while thanking him for everything he has done. Dazai, so shocked by his gesture of kindness, passes out.

In the light novel, 55 minutes, Atsushi notices something amiss about the case they have been assigned on the island they're travelled to. Atsushi is forced to infiltrate a group of thieves and Dazai, in true Dazai fashion, suggests the nickname Matasaburou of the Wind for Atsushi to use as an alias. It is revealed that he chooses this name purely for his own amusement, messing with Atsushi yet again. There are also several sentimental moments between them during the novel. In a memory, Atsushi, while following along behind Dazai, comes to the realisation that Dazai is not completely flawless and has many human faults, contrary to what he once believed. When he finds himself in possession of some information that no one else can know, Atsushi disobeys the warning he is given by H.G Wells and tells Dazai the information anyway, despite knowing there could be catastrophic consequences should things go wrong. After being advised by Kunikida, Atsushi is sure Dazai will figure out exactly what to do. Towards the end of the light novel, Dazai ends up in mortal danger due to a stab wound and Atsushi is tasked with saving him. In an effort to reach Yosano, who can save Dazai, Atsushi encounters the main antagonist of the novel. During this scene, an unusually aggressive side of Atsushi can be seen, spurred on by the desire to save Dazai. Violent side is even noted by the antagonist himself. Atsushi is asked by Jules Gabriel Verne if he wishes to save Dazai, to which he responds ' ''Of course. No matter what it costs.'''

Fanon
Dazushi is the third most written ship within the fandom on AO3; Dazai's second most written and Atsushi's second as well.

Fandom
FAN FICTION
 * Atsushi/Dazushi tag on FanFiction.Net
 * Atsushi/Dazushi tag on FanFiction.Net

INSTAGRAM 
 * @deviant.dazushi account related to Dazushi ship on Instagram.
 * @mrsdazushi account related mostly to Dazushi ship on Instagram.
 * @jinko.tiger account related to Bungou Stray Dogs (but there's a lot of Dazushi) on Instagram.
 * @bsd.shipping.hell account related to BSD ships (there's a lot of Dazushi) on Instagram.

YOUTUBE
 * Ocehamada have a few Dazushi related (awesome) edits on Youtube.

Trivia

 * In a lot of moments when Dazai and Atsushi are together, we can see the sunset in the background - one of the backgrounds that are described as the most romantic scenery.
 * They have a duality card together in the mobile game 'Bungou Stray Dogs: Tales of the Lost', as well as several cards with subskills that activate when a card of the other is on the team.