Odazai

Odazai  is the slash ship between Oda Sakunosuke and Osamu Dazai from the Bungou Stray Dogs fandom.

Canon
The meeting between Oda Sakunosuke and Osamu Dazai is still a mystery.

The relationship between Oda and Dazai, is inserted over a period of time of Bungou Stray Dogs called Dark Era.

In this arc of time, the young executive Dazai seems to care a lot about his only friend, except Ango Sakaguchi, Oda.

Their relationship takes place in the anime, manga and the Dark Era Novel, written by Asagiri Kafka.

Dark Era
In the anime, Dazai and Oda, along with Ango, are used to drink together at the Lupin. However, it doesn't appear Dazai drinking what he ordered, he only talks to Oda and Ango. Sakunosuke, during his meeting, has declared that he finds Dazai really interesting, and Dazai has replied with "No way, you're more interesting than me!". Plus, Dazai refers to Oda with the nickname "Odasaku", which is in Japan a nickname for only close friends or someone who is in a close relationship, Osamu calls only Oda with that affectionate nickname.

When Oda is around, Dazai seems to be happier and his facial expressions soften in a sincere smile.

Dead Apple (and a little of the Beast AU)
In one of the first scenes from the movie we can see Dazai sitting by Odasaku's grave. Atsushi notices him and starts a conversation with Osamu in which we can find out a little more about Odazai's relationship. Nakajima asks Dazai if that person was dear to him. Osamu doesn't give a direct answer, but we can see a little smile for a second, which probably confirms it. Atsushi also asks him "was it someone you were in love with?". Osamu answers that if it was a women he loved, he'd died with her. Well, he did commit suicide because of Oda's death in Beast AU light novel, didn't he?

Beast AU
In one of the light novels from the Bungou Stray Dogs series, the "Beast" novel, Dazai creates an alternative universe in order to save Oda. The one in which the novel is set isn't the first alternative universe he created. In fact, he attempted several times to save him, but always failed. The only time Dazai managed to save Oda was when the two had not made friends with each other, that is the universe in which the novel is set. This is the reason he decided to sacrifice their friendship: Dazai preferred a world where Oda was alive but not his friend instead of a world without Oda. One day Dazai managed to meet Oda at the Lupin Bar. At first Oda didn't know who Dazai was and the two of them just talked. In that situation Dazai acted kindly and politely and he smiled quite awkwardly, especially when he accidentally called Oda by his nickname "Odasaku". However, the two conversed in a way very similar to the way they conversed in the canon universe, full of bizarre discourses from Dazai and calm responses from Oda. However, when Oda, who was in the Armed Detective Agency instead of the Port Mafia, learned that the man he was talking with was the Port Mafia's boss, he became quite hostile. He pointed his gun at Dazai and when he called him by his nickname, Oda harshly replied "Don't call me Odasaku". These words really hurt the mafia's boss, as stated in the novel: After their meeting, Dazai then takes his own life by falling from the rooftop where he met Atsushi and Akutagawa for the last time. His last words were:

Fanon
A lot of people from the fandom believe that Dazai was actually in love with Oda. Not only shippers. Additionally there's a lot of hints telling that it might be a true theory. But we can't be 100% sure yet, since - as it's kind of written in the canon section - some of the things about their relationship are still a mystery.

Fandom
FAN FICTION