You had made a deal with someone in the dark. This allowed you to enter survey corps and be beside your favourite levi-nii. The love you had for him had been since a long time but he never knew.
You weren't real blood siblings but at least he cared you so like a sibling... since the day both of you met.
You were supposed to be dead but yet you appear in front of him with another name.
Your other name... Keria.
P.s. if you don't like Reader having a name. Don't read. Comments to particular issue will be treated with hostility by author-chan desu.