Before Erwin, Levi "bonded" with someone else. She will always be Erwin's little sister first, and anyone else second. And her smile—oh her smile—dares Levi to fall in love with her. It is a madness, a terrifying feeling of devotion, a forbidden pleasure all at once—yet there is always a charm about the forbidden that makes it unspeakably and painfully desirable. [w/ sexual themes]