EreMin

Eremin is the Slash ship between Eren Jaeger and Armin Arlert in the Attack on Titan series.

Canon
The creator of the series said that they are so close that weird rumours spread about them, though he also said that they may not stay best friends forever. Their closeness has been pointed out by Historia Reiss as well as Jean Kirstein. Eren often defended Armin from bullies when they were children, which usually resulted in Armin holding him back so he wouldn't end up hurting himself. These two have one of the strongest bonds in the series, which is shown time and time again by their constant care for each other from childhood to adulthood.

Fanon
Fans have noticed their close bond that they maintained for years, such as joining the military and fighting alongside each other to reach their goals of seeing the ocean, which lies beyond the walls. Though it is still in question whether their friendship will last or progress into something more (or even less) they have strong feelings for each other in canon.