All Wraith
The Dark Wraith was Darth Vaders secret apprentice. While Vader and the Emperor hunted down the remaining Jedi survivors, Vader new that if his apprentice was a Force user the Emperor would detect him. So Vader had to search for someone without Force capabilities and found Wraith. Although possessing no Force capabilities, Wraith was an extraordinary swordsman and that quality is what interested Vader. He began to train Wraith in a scheme to overthrow the Emperor.
Additional note : My Son and I created the idea that no ordinary individual can activate a Light Saber. You must posses Force capabilities to use the weapon. Wraiths sabers were constructed by Vader himself using his own DNA to activate the crystals enabling Wraith to use the weapon at the push of a button.