You can't really have NiGHTS without his malevolent sibling, Reala, now can you? So here he/she is, on his/her throne. I couldn't really think of a good cutie mark for him/her, so I just decided that perhaps Nightmaren ponies don't get cutie marks.
Reala was actually bit more difficult than NiGHTS. He/She has a odd outfit, especially the gloves. The claws on said gloves are primarily for decoration, since it would be difficult for him/her to make a slashing motion with his/her front legs.
Shout out to for the pillow vector used in the throne.