3. Saruman

Saruman contacting the Dark lord Sauron

Being chief of the wizards and white council that opposed Sauron one would think that he would be a hero not a villain. After extensive studying on the ring he grew to desire the ring for himself and thought he could ally with Sauron and then eventually betray him to gain the ring and its power. His ultimate goal was to betray everyone to eventually become the ruler of Middle-Earth. His overwhelming lust for power eventually led to his downfall at the battle of Isengard where he was cast from one of his towers.

Using his influence and power to train Uruk-Hai

LOTR The Fellowship of the Ring - The Fighting Uruk-hai