Morgoth Bauglir (originally Melkor) is a fictional character from J. R. R. Tolkien’s Middle-earth legendarium. He is the main antagonist of The Silmarillion, figures in The Children of Húrin, and is mentioned briefly in The Lord of the Rings.

Melkor was the most powerful of the Ainur, but turning to darkness, became Morgoth, the ultimate antagonist of Arda, from whom all evil in the world of Middle-earth ultimately stems. Sauron, one of the Maiar of Aulë, betrayed his kind and became Morgoth's principal lieutenant.

Morgoth was the principal agent of evil in The Silmarillion, and his influence lingered in the world even after he was cast from the world into the outer void. Morgoth's example provided later ages a cautionary tale against pride, wrath, envy, lust for power, and greed — and the destruction these visit upon oneself and others.