Neysa is a unicorn mare who met Stile when he first came to Phaze. She has the ability to transform into a unicorn, human, or firefly. Her horn sounds like a harmonica. She is the sister of Clip. Neysa is known for being an excellent runner. She generally isn't very talkative.
As a unicorn, she has a black coat with white socks. Due to the color, she was shamed upon in Split Infinity because unicorns generally don't have the same color coats a normal horse would. She is also small for her species, at 14 hands tall.
When she is human, she is depicted with jet black hair and being shorter than Stile, who is about 4 feet and 11 inches tall.