Board Thread:Speculation House/@comment-14138255-20141024002244/@comment-24891101-20141024010727

One, human-form Grimm are almost certainly nonexistent, since it breaks the motif, and she used a weapon and Semblance, which would be impossible.

Two, it's not Summer, it's clearly Yang's mom. Why else would she get a glimpse of her as she leaves. Besides, she looks a lot like the Transient Princess, who we all know (with decent confidence) is Yang's mother.