Luna (My Little Pony)

"You no longer have reason to fear us. Screams of delight is what your princess desires...not screams of terror."

- Princess Luna

She is Princess Celestia's younger sister and Equestria's co-ruler, in the first episode of season one, she was the antagonist Nightmare Moon who threatened to create an eternal night. She was later purged by the Elements of Harmony, and was invited by her sister to rule by her side.

She later appeared in a season two episode, were she tried to convince the others that she wasn't evil, but ended up being enraged to the point of almost cancelling Night Mare Night (Equestria's equivalent to Halloween). She also aided her sister in defeating Discord a millennium ago.