EruNile

EruNile is the slash ship between Erwin Smith and Nile Dok from the Attack on Titan fandom.

Canon
Erwin and Nile were both from the same division as they were undergoing the training program as cadets. Not only were they fellow cadets, they became good friends. When they were still young they fell in love with the same woman, Marie, although Nile eventually married her after joining the Military Police. After this, their relationship became quite strained, and they talked much less often.

First Erwin and Nile are seen together during the trial of Eren Jaeger. They have clashing opinions on the matter, as Nile wants to demolish the threat he emanates, while Erwin sees Eren as a potential ally. Due to Levi Ackerman's involvement the conflict is resolved by Darius Zackly letting Eren serve under Erwin's orders. The decision leaves Nile unsatisfied. Later he asks Erwin about his plan to retake Wall Maria. After the initiation of the operation to detain the Female Titan, Nile learns from Erwin the identity of their enemy. Later Nile commissions several members of the Military Police to assist Erwin and the Survey Corps in capturing the Female Titan. The two are seen together at the military meeting aftr the events. However, it is cut short when they learn that Wall Rose has been breached and Erwin rushes to investigate, while Nile sends members of the Military Police but does not go himself.

When Erwin starts planning coup d'état, he warns Nile that protecting one's position and protecting one's family may be two dirrefent objectives, and it's important to choose wisely. This makes Nile suspect Erwin has something dangerous planned for them. When Erwin is arrested on the false accusation of being a murderer, Nile visits him in his cell, letting him know about his audience with the King. Nile expects the Survey Corps to be disbanded as soon as Erwin is executed. Erwin asks Nile how his family is doing and where they are currently living. Stunned Nile says that he has not been home in a while and confirsms that they are currently in the eastern section of Wall Rose. Erwin mysteriously tells him that if something arises, he will be waiting for Nile's decision.

When the meeting with the King goes awry and Erwin is sentenced to death, Nile looks visibly upset. When the news break about the fall of Wall Rose, Nile remembers his conversation with Erwin and realizes that Erwin knew this would happen. Nile tries pleading with the officials and nobles, saying that they should let the refugees in and it won't lead to a civil war. Nile declares that he stands with Wall Rose, even if it means opposing the crown. When Darius Zackly announces the fall of the current regime due to their inability to react to crisis rationally, Nile turns to Erwin and smiles admitting Erwin won. Erwin, however, looks unsettled as he warns Nile that humanity has been forced onto an even more dangerous path.

Junior High Manga
In the Junior High Manga, Erwin and Nile are close friends and work well together. After Nile was accused of being a womanizer, and even kicked out of his house, Erwin was willing to help Nile. This ended in Nile pinning him down in front of Marie, making the impression that they were together. The situation was fixed before Marie and Nile's third child was born.

Fanon
EruNile has a rather small fanbase, due to Nile's lack of screentime compared to other characters. Most fans see them as old friends. However Erwin and Nile's past together was noted by the fans, who sometimes specualte whether the two were closer when they were undergoing training together. It is also considerably interesting that the two shared their affection for a young woman called Marie. Fans often compare Nile and Erwin, drawing conclusion that the two were in a similar situation, but due to them being irrevocably different in nature, they chose different paths. Nile chose a safe route that allowed him to minimize the risks of dying, while having a stable job, and being with the person he liked. Erwin chose a thorny path, discarding his afferctions to pursue his dream.