Ackerman's Sister || Levi x Sister Reader x Erwin

It's no secret that Levi Ackerman is a very strong yet distant man set on keeping the most intimate details of his life hidden away from even his own squad, one of those details being the fact that he once had an older sister in whom dedicated everything she had to ensure his survival in the cruel world they lived in. At last, Levi's new squad will learn her story and how Levi became humanity strongest man.