Morgoth is the first Dark Lord in J.R.R. Tolkien’s mythology.
Originally called Melkor, he was one of the powerful Ainur who entered Arda at its beginning. He rebelled against the intended order of the world and became the principal enemy of the Valar and the Elves. After committing major acts of destruction, he was known as Morgoth Bauglir, meaning the Dark Enemy or Black Foe.
Morgoth is the central antagonist of much of The Silmarillion, especially the First Age stories. He steals the Silmarils, jewels made by Fëanor, and holds them in his fortress of Angband. His wars devastate Beleriand and shape the tragedies of characters including Beren, Lúthien, Túrin, and the children of Húrin.
Sauron was originally one of Morgoth’s servants, not the first Dark Lord. After Morgoth’s defeat and expulsion from the world, Sauron became the chief enemy of the later ages.