You were Erwin's kid. After his death, Levi and Hange found it their responsibility to tell and take care of you. They knocked on your door before entering. In the short time you knew them both, you could see the saddened expression on their faces.

When they told you, Hange let you embrace them with a hug. Whereas, Levi just stood in the corner of the room. A strange sensation filled the room. It was one you hadn't felt before.

"I'm sorry..." Levi mumbled.