So What if Misty in a very young age Wasn't raised by Opaline but was found by None other than Formal Storm army Commander Tempest Shadow, Who is a Princess herself (Although didn't added her re-grown horn and wings).

Or if Opaline was very hard on Misty as she left the castle in grief and was found by Tempest who is actually still alive and more Friendly as well caring, She would be Misty's guardian angle as Tempest had experiences on being Treated as a tool and they have a true like Mother and Daughter bounding.

I did made a Comparison towards Tempest and Misty as they are both Unicorns with Tragic stories as well being used by their Evil Bosses who seek Power and ended up being Betrayed, Either way We will see how Misty's Story continues on how she will be free from Opaline's abusive, cruel, heartless nature.