2. The dark lord of the Second and Third Ages had many names, Mairon, Gorthaur, the Necromancer, Annatar, and more. He settled in Mordor and was the ruler of the One Ring. What was his most common name?
From Quiz Tolkien's "S" Characters
Answer:
Sauron
Probably the mightiest of the Maiar, Sauron was not always evil. He learned how to create things under the Vala Aulë, and was disdainful of waste. However, he saw Melkor as a means to his end and fell under his sway. He rose quickly in the ranks of the original Dark Enemy and was equal in rank to Gothmog, Lord of the Balrogs. When Melkor was taken and cast into the Void, Sauron began amassing the remnants of Melkor's followers and settled in Mordor. To ensnare all of the Free Folk, Sauron was instrumental in the forging of the Rings of Power, and to rule them all, the One Ring.
Sauron was eventually brought down in the War of the Ring by the most unlikely of heroes, a Hobbit named Frodo. When the One Ring was cast into the Cracks of Doom, Sauron's power was undone and his physical form was cast away. His spirit began to float above Mordor only to be blown away by the wind. While it does not explicitly state that Sauron died, we do learn that when the source of his power was destroyed, he ceased to be mighty.
'Sauron' is a Quenya word meaning 'abhorred'.