Melkor

[Nilore]

Here is a lot of info on the first DARK LORD:

To be precise Melkor or Morgoth as he was later know is not a Dark Servant of Sauron...
...in fact quite the reverse is true.. Sauron was a disciple of this ancient evil in Middle Earth. Sauron was the student and Morgoth was his teacher.

A mear shadow of a Darker and deeper Evil.

In his ancient fortress of Angband, far to the north of Beleriand, he made an Iron Crown for himself, with the Silmarils mounted upon it.

Melkor' is the true name of the first Dark Lord, and is used for him from his Beginning until his theft of the Simarils.

Events of that period are described in this entry, but for events after his return to Middle-earth at the beginning of the First Age, see the entry for Morgoth Bauglir.

Said to be the mightiest dweller in Arda, Melkor was of the same order of the Valar and equal in power to Manwë himself, who was Melkor's brother in the mind of Ilúvatar. While the Valar descended into Arda to order and govern wisely, though, Melkor sought power for himself alone, and sought to bend all things to his own will.

All that the Valar made, Melkor looked to destroy; long before the Elves awoke, he threw down the Lamps of the Valar, destroying their dwelling in Almaren. They removed to Valinor, and fearing for the coming Elves, made war on Melkor and imprisoned him for three ages.

By the time he was released, the Elves had come to Valinor; Melkor turned back to his evil ways; slaying Finwë and stealing the Silmarils, he destroyed the Two Trees of Valinor and fled back to his ancient fortress of Angband in the north of Middle-earth.