My Little Pony Coloring Pages: Luna has a dark blue coat, a mane that resembles the night sky, and her cutie mark consists of a crescent moon. Her regal appearance reflects her role as the princess of the night. Princess Luna initially appears as the antagonist in the two-part pilot episode of the series, where she transforms into Nightmare Moon due to feelings of jealousy and resentment. She is later redeemed and becomes a key figure in Equestria.