EreMin

Eremin is the slash ship between Eren Jaeger and Armin Arlert from the Attack on Titan fandom.

Canon
Eren and Armin met each other as young kids in Shiganshina. One day after an encounter with bullies, Armin was approached by Eren who was curious as to why he had not defended himself. Armin replied that he had not lost since he did not run away, to which Eren asked his name.

The two of them soon became best friends and would often talk of what lay beyond the walls, inspiring each other to see for themselves. Both being outcasts, the two only really had each other before Mikasa came along. Eren, along with Mikasa, would often defend Armin from bullies.

Eren and Armin both enlisted in the 104th cadet training corps at the age of 12. On their first mission against the titans three years later, Eren saved Armin from getting eaten by pulling him out a titan's mouth and taking his place. Armin screamed and fell to his knees when this happened, and later broke down whilst breaking the news to Mikasa. To Armin's shock, Eren survived using his titan shifter abilities. Upon seeing Eren alive Armin became emotional and held his hand.

After being captured by the Garrison, Eren transformed once again to shield Armin and Mikasa from cannon fire. He then put all his faith in Armin to convince the soldiers to spare their lives - and it worked. Soon after, Eren attempted to block the hole in the wall using his titan form, as proposed by Armin. Shortly into the mission, Eren knocked himself unconscious. However, he was soon back up on his feet thanks to Armin's motivational words and, thus, managed to successfully plug up the wall. Armin tried to pull Eren out of his titan afterwards and held Eren's arm over his shoulder.

On the Scouts' 57th expedition, Jean told Armin that he'd always found Armin creepy for his attachment to Eren, suggesting he thought they were a bit too close to just be friends.

After Annie's transformation when Eren was lying injured under rubble, Armin motivated him to fight, yet again, by encouraging him to let go of his humanity.

Armin helped rescue Eren from Reiner and Bertolt by emotionally manipulating Bertolt into letting his guard down. After Eren was retrieved, the two of them, along with Mikasa and Jean, rode their horses together in silence while morning the loss of Hannes.

The evening before the Shiganshina mission, Eren, Armin and Mikasa sat outside and reminisced about their childhood. Armin excitedly reminded Eren of the sea and the other various wonders of the outside world, having him promise that they will go there one day, to which Eren smiled and agreed to. When Eren was shaking on their journey to Shiganshina, Armin reminded him of the time when Eren fearlessly rescued him, and Eren revealed it was a memory of Armin talking about the outside world which gave him the courage to do so. Eren stopped shaking and thanked Armin.

During the Battle of Shiganshina, Armin convinced Eren to go with his plan to beat the Colossal Titan, even though it meant his own death. After capturing Bertolt, Eren looked at Armin's burnt body with a sad expression. When Armin started to breathe again, Eren moved close to him and became tearful. At Levi's arrival on the scene, Eren urged him to let him save Armin with the titan serum. Levi's decision to save Erwin instead caused Eren to stand in his way. After being punched by Levi and restrained by Floch, Eren once again attempted to save Armin by telling Levi about Armin's worth as well as his dream of seeing the ocean. In the end, Armin got saved and, upon waking up, he received a big, teary hug from Eren.

A year later, they finally made it to the ocean. While Armin was happy about this, Eren could not share his happiness because he knew that, beyond the ocean, their enemies lay in waiting. Eren and Armin soon developed differing ideas on how to deal with the Marleyans. As shown in the shooting range scene, Eren wanted to fight them while Armin was content with slowly earning their trust and making friends with them.

After his attack on Liberio, Eren was helped on board the Survey Corps' blimp by Armin. The latter's expression, however, was not very welcoming, as he did not agree with Eren's ruthless actions. When they returned to Paradis Armin confided in Annie that he no longer understood Eren.

Isayama said that Eren and Armin are so close that weird rumours spread about them, though he also said that they may not stay best friends forever.

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. 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.