A duel in the Works erupted between Count Dooku—a former Jedi Master who had been secretly working with the Sith Master Darth Sidious—and Jedi Master Yaddle. After Yaddle followed Dooku, who had been hiding his Sith dealings by use of the code name "Tyranus," to the LiMerge Power building, the two engaged in a lightsaber duel, which resulted in her death. In the aftermath of the duel, Dooku fully succumbed to the dark side of the Force and became a Sith Lord under the name Darth Tyranus.