A shadowy creature of Elvish legend, sent by Melkor to trouble the first Elves at Cuiviénen. A dark figure on a fearsome horse, he was said to steal away wandering Elves, and indeed it is possible that those taken by the Rider became the first of the Orcs.

Morgoth's choice of a Rider on a mighty horse may have been part of a plan to estrange the first Elves from the Vala Oromë, who also rode a great steed. If so, the plan failed: Oromë did indeed discover the Elves under the starlight of Middle-earth, and though they were alarmed at first, many overcame their fear of him and even followed him into the West.

As for the dark Rider himself, he is never mentioned after the coming of Oromë and the Great Journey into the West. Perhaps he still pursued the Avari who remained in the shadows of the east, but he faded from the tales of the Eldar. Thousands of years later, Sauron's servants, the Ringwraiths, also rode across Middle-earth as Black Riders on black horses, perhaps following the form of Morgoth's own dark Rider from the depths of history.