EreAnnie

Ereannie is the het ship between Eren Jaeger and Annie Leonhart from the Attack on Titan fandom.

Canon
Eren and Annie met each other as trainees in the 104th cadet training corps. They became sparring partners and Annie taught Eren some moves which he would later use on both Jean and Reiner. Eren saw past Annie's cold exterior and respected her for her insight. In return, Annie respected Eren for his courage to 'go against the flow'.

Annie infiltrated the Survey Corps' 57th expedition to try and capture Eren as part of her mission. The two of them battled in titan form (Eren unaware of her identity) and Annie ripped Eren out of his titan's nape. However, he was soon rescued by Levi which left Annie crying.

Eren became incredibly defensive of Annie when Armin put forward his theory of her being the female titan. When they cornered Annie and she admitted to it, Eren shouted at her to stop kidding around. Even after witnessing her transformation in the flesh Eren struggled to accept reality and still couldn't transform to fight her, causing a paranoid Mikasa to question his feelings for her.

During their second hand to hand titan battle, Annie once again had the upper hand against Eren. However, with the help of Mikasa, Eren was able to pin her down and rip her titan's nape off. At this point Eren froze at the sight of Annie's crying face and this hesitation was what gave Annie the opportunity to crystallise herself.

Eren notably displayed far less anger towards Annie after learning her identity in contrast with Reiner and Bertolt, suggesting he had somewhat of a soft spot for her.

In the Junior High anime it is heavily implied that Annie has a crush on Eren and the two of them bond over their shared love for cheese burger steak.

Fanon
Post time-skip, Eren and Annie are arguably just as villainous as each other. Both have killed hundreds of innocent people - both directly and indirectly. However, both did so against their will and with the intention of helping humanity. When they speak again it is likely they will have a deeper understanding of each other due to their shared experience, and this may lead to something more over time. Due to her resentment towards Marley, there is a high chance that Annie will switch sides and fight for the Eldians when she is broken out of her crystal, which would make her and Eren allies.

Fandom
AO3