This Sith Lord was pretty much impossible for the Jedi Knights to find, even though he was right under their noses the entire time. It's much easier for you to find the wicked Darth Sidious, by simply heading over to LEGOStarWars.com. Once you're in, hit ENTER, then type DARKSIDE all as one word, then hit ENTER again.
His angry scowl should greet you... warmly?"
Click here for link (via: starwars.com games legoswiii)