Princess Luna

Princess Luna is the sister of Celestia and Harmonia, adoptive aunt of Princess Cadence, aunt of Discord and great aunt of Rue Day and Flurry Heart Sparkle. She is the co-ruler of Equestria, princess of the night, and a member of the Royal Family of Equestria.

Twilight Sparkle
Twilight first started out as Princess Luna's enemy while under the guise of Nightmare Moon. However, after Twilight and her friends use the element of harmony to restore her back to normal, Luna is once again the kind-hearted pony she once was. Twilight later helps her bring back the respect of the citizens of Ponyville.

Rue Day
Rue has respect for Princess Luna. It is revealed that Luna's other sister, Harmonia is Discord's mother, thus Rue Day is Luna's great-niece. Luna treated her like a daughter, knowing what it was like to be an outcast.