Possible Clues:

• "Star Wars" order
• 'Star Wars Episode III: Revenge of the ___'
• Jedi's opponents
• In Star Wars, those using the dark side of the Force
• Lightsaber wielders who are enemies of the Jedi
• Fictional group led by a Dark Lord
• 'Star Wars' side with red lightsabers
• Group once led by Darth Sidious
• Order of Darth Sidious
• 'Star Wars' baddies