To be clear this is Tanwen! Just, transformed into a copy of me (Cradle) :3 The clothes are the first clue, but the really proof is in the asterism—that is, the stars on her face—which constinues to shine through no matter what masks, transformations, or illusion magic you throw at it. And if Sparkles can't hide something with an illusion, if Sparkles can't even dim something with an illusion... That's certainly something. The reason she doesn't have wings is that the twinning ritual didn't make her a demon. That's Tanwen as regular-old-mortal Cradle.