Morgoth
Morgoth was once a Vala named Melkor. However, he became jealous
of the power of the Creator Illúvatar, and challenged
him for control of the heavens. Losing, he was cast down to the world below, and barred
forever from the skies. Furious, Morgoth made war on the Valar living in the Undying Lands, and succeeded in destroying much that was good in
the world. Finally, he was driven back and cast beyond the doors of the world by the
Valar.
His chief lieutenant Sauron remained, and continued to plague the
world with evil, using the corrupted races that Morgoth had
made as his weapons, and the greed of men as his greatest ally.