Fyolai

Fyolai is the slash ship between Nikolaj Gogol and Fyodor Dostoevskij from the manga and anime Bungou Stray Dogs.

Canon
Nikolaj refers to Fyodor with the friendly nickname "Dos-kun", yet he doesn't seem to be bothered at all. He also isn't annoyed by Nikolaj's loud and cheerful behavior.

Bonus chapter
There aren't many scenes where the two of them are really close, or rather the dynamics are almost zero. We only see them talking to each other directly in the bonus chapter at the end of the 14th volume of the manga. The bonus chapter (consisting of just two pages) is about Nikolaj wanting to play a game with Fyodor while he is still learning the Japanese language. Fyodor goes along to Nikolaj's desire even though he isn't very interested. He then fools Nikolaj with a word catch and Nikolaj loses the game.

Chapter 58
In chapter 58 of the manga (14th volume), when Nikolaj explains to Atsushi the reasons behind his murderous actions, Atsushi says that he still doesn't understand his motives and his idea of "true freedom" at all. and Nikolaj answers by saying: "I suppose so. In the end, the only one who understands is Dos-kun".

Chapter 78
In this chapter it is finally revealed that Nikolaj is still alive and that he faked his death. According to Sigma's words, Nikolaj was indeed supposed to die, without any kind of trickery, however Nikolaj was able to save himself with the use of his supernatural ability. When the plan was arranged by Fyodor, Nikolaj agreed to die in order to prove his thesis of "true freedom" and "true free will", however he changed his mind, probably when speaking to Atsushi or to the vice minister of justice Tonan. It is unknown whether Fyodor predicted that Nikolaj would change his mind. When Nikolaj talks to Sigma, he says once again that Fyodor was the only person who was able to understand Nikolaj's idea of "true freedom". He also says that he was deeply moved by Fyodor's words and that he was his first and only friend. His "intimate friend".

Nikolaj then says the reason he changed his mind about him dying according to plan. His concept of being "truly free" means being freed from his own feelings and, since he said that he and Fyodor have a very close relationship, he thinks that by killing him he would prove to be truly free.

Fanon
In the fandom it isn't really believed that this ship could be canon, however we all agree to the fact that Nikolaj truly admires and cares for Fyodor, even though he wants to kill him because of his rather twisted idea of freedom. Some people think that Nikolaj could develop an obsession towards Fyodor that might lead him to becoming similar to the yandere trope.