in world of My Little Pony but this one is humanoid so feet and hands. where magic and the many races live together, with the 2 royal sisters being Celestia and Luna but in this universe Nightmare moon became a separate entity

Origin of her transformation: Nightmare Moon is the corrupted form of Princess Luna, who became jealous of her sister Celestia. Luna felt unappreciated because ponies celebrated Celestia's daytime while ignoring the night she brought.

Bitterness, This resentment festered over time, turning her into Nightmare Moon—a manifestation of her anger and desire for recognition. Nightmare Moon sees herself as powerful and superior. She speaks in grand, formal language, often with an air of menace and drama.

She believes her night is beautiful and worthy of eternal admiration, and she looks down on others who don’t recognize that. She desires revenge against Celestia and the ponies of Equestria for the perceived injustice of being unloved and ignored.

Nightmare Moon is cunning, setting traps and manipulating She’s not a mindless villain, she has a plan and executes it with calculated moves. At her core, Nightmare Moon is a tragic character. She represents Luna’s pain and isolation, making her more complex than a typical villain.

deep inside the castle underground dungeon sits Nightmare moon her black skinned feet are trapped in a metal stock that's made from Lunar metal that blocks magic in its area, As Her toes are held back from a spring tention lock preventing any movment. Moon (shorter name for Nightmare Moon) will say anything for somone to let her out