Character: nitemare (zombienuke1)
Nitemare is a female horse with dark fur and blue hair/tail as well as blue eyes.
Nitemare was an adoptable created by the artist "Keel the Equine" before being acquired by the Furaffinity user "zombienuke1" in 2018.
Original Artist: https://www.furaffinity.net/user/keeltheequine
Character Owner: https://www.furaffinity.net/user/zombienuke1/