Sauron

Sauron, also known as the Dark Lord of Mordor, is the main antagonist of The Lord of The Rings Trilogy, he serves as a central background antagonist in Middle-earth: Shadow of Mordor, the main antagonist and final boss in The Bright Lord Story Pack, and highly likely the main antagonist of the upcoming Middle-earth: Shadow of War. He was Morgoth's most powerful lieutenant and the mastermind behind many of his schemes, and the forger of the One Ring. While Sauron lived, he was feared throughout all of Middle-earth, even to the farthest reaches of the world.

Trivia

 * He is The Main Villain of Po's Adventures.
 * He is also Po's Arch Nemesis.
 * Even though he is a villain, it is revealed that he is in love with Hela.