Night Stalker doesn't appear in the original minicomics, but he has appeared in the UK comics by London Editions. Some versions depict it as Jitsu's evil robotic steed, others as the "reincarnation" of the heroic Stridor.
Unlike the consistent portrayal of Stridor, the UK comics alternate between having Night Stalker with his robotic appearance or as a normal horse with just the colors of the toy.
Interestingly enough, Filmation's He-Man model packs show that Night Stalker was meant to be in the show. In the Model Packs he was referred as "Knightmare".