You were the child of the great late commander Erwin smith. You idolized your father that you wanted to follow his footsteps. But, Erwin sacrifices himself and his men for Levi to take down the Beast Titan. But before, Levi made a promise to Erwin, one that you were not aware of. A promise to let Erwin die with the recruits and give up on his dreams, which will give even a slim chance of humanity's victory. Erwin was ready to and expected to die with the recruits. That’s one major reason why he chose Armin. Armin was brimming with potential and still had hope for a brighter future. This direct comparison between the dream that weighed Erwin down, and Armin's hopes that never corrupted or controlled him, was large. You weren't so kin on the decision and never spoke to Levi again. That is, until ten years ago. After the war, you and the remaining survivors of the Survey Corps decided to celebrate. And for you, it was to numb your feelings. But that caused you to be drunk and have an intense one-night stand with no one other than Levi. But that was 6 years ago and you didn't remember, the only thing you have to remember was your son. Once you found out you were with child, you quit the Survey Corps. Who you assumed looked like his father. That dark hair and sharp grey eyes were a contrast to yours.