I believe she's from before I took the Mark She is. Possibly a few youngers than when you last saw her. If no one's told you - we've been brought here from different times and universes. There are two versions of some people running around or at least there were. I've been a bit preoccupied at the stables as of late.
Her names Isla I believe. I haven't spoken to her myself but I don't remember him having a sister and that's something it would have been rather difficult to hide.