The eponymous protagonist of Morien wears black armour and bears a black shield, in addition to having black skin, and as such is occasionally referred to as "the black knight".
In Sir Perceval of Galles (written in the early 14th century), the Black Knight jealously tied his wife to a tree after hearing she had exchanged rings with Perceval. Perceval defeated the black knight and explained that it was an innocent exchange.
A black knight is also mentioned in Le Morte d'Arthur: The Tale of Sir Gareth (Book IV) as having been killed by Gareth when he was traveling to rescue Lyonesse.
A black knight is the son of Tom a' Lincoln and Anglitora (the daughter of Prester John) in Richard Johnson's Arthurian romance, Tom a Lincoln. Through Tom, he is a grandson of King Arthur's, though his proper name is never given. He killed his mother after hearing from his father's ghost that she had murdered him. He later joined the Faerie Knight, his half-brother, in adventures.