AruAni

Some suggest that Armin is in love with Anna, but this is not true. Armin doesn't really love Annie, he was kind to her, nothing else. Annie doesn't love him, she just respects him.

Canon
In the "sudden visitors" OVA Annie and Armin are together for the whole of the episode while trying to assist Jean.

While having their gear inspected, Annie subtly tries to persuade Armin not to join the Survey Corps and recognises his strong spirit, showing some level of care as well as respect.

On the Survey Corps' 57th expedition Annie spares Armin's life twice whilst in Titan form even though she slays everyone else. This is despite the fact that Annie was probably aware that Armin would be able to use his wits to identify her. Armin, however, waits two months before saying anything because he desperately wants to be wrong for once.

Armin emotionally blackmails Annie into helping them even though she knows it is a trap. Annie admits that she couldn't understand as to why she didn't kill Armin before, and she seems hurt by his betrayal. During her fight with Eren, Annie spares Armin's life yet again despite Armin trying to goad her into killing him.

When the crew captures Hitch and Marlowe, Hitch mentions Annie because she thought she died during the battle of Stohess, she also says "She didn't have any friends right?", Armin's reaction to this is apparent and Mikasa notices it, she can be seen staring at him in multiple panels.

As an outcome of the Battle of Shiganshina, Armin inherits Bertolt's memories and has since gained a much deeper understanding of Annie and her past, due to being turned into a titan and eating Bertolt. Four years on Armin is seen confiding in Annie, even though she is still in her crystal form, and makes an emotional appeal for her to respond. He doesn't seem to resent her for the things she has done having now experienced the anguish of being the bad guy.

On Armin's next visit he tries touching Annie's crystal. Hitch appears and asks him to take his hands off her. Armin becomes very flustered and blushes as he tries to explain himself, then begs Hitch not to ban him from coming.

On the ship to Marley, Annie asks Armin to take a seat next to her and thanks him for coming to visit her while she was in the crystal. She was confused about it, saying that there were probably more entertaining girls that he could've spent time with, but Armin says it was because he wanted to see her and that she should understand from hearing Hitch's teasing to Armin.

When the team is getting the flying boat ready for deployment, Mikasa talks to Annie. Annie says she isn't going to fight anymore and says she wants her last moments to be in peace as she looks at Armin. Mikasa notices this and looks at Annie with a surprised expression, Annie blushes in response to this.

Fanon
Some theorize that, given that Bertolt loved Annie, it is possible that Armin now has romantic feelings for her. He even acts embarrassed and defensive, just as Bertolt did, when the subject of his feelings for Annie comes up.

Fandom
FAN FICTION
 * Armin/Annie tag on FanFiction.net
 * Armin/Annie tag on FanFiction.net

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