Sauron is definitely the most fitting for the title of Dark Lord, both politically and personally. Merely touched by things he creates, or even things his minions create, will begin to corrupt you to your own darkness, and he is the most active conqueror out of all of these.
Then again, Sauron is nothing more than the sole surviving henchman of Morgoth, who deserves the title far more (Quite possibly the second or third most powerful being in the entire Tolkien mythology).
Then again, Sauron is nothing more than the sole surviving henchman of Morgoth, who deserves the title far more (Quite possibly the second or third most powerful being in the entire Tolkien mythology).