Sylvanas Windrunner - Wikipedia
World of Warcraft’s leaked cinematic has fans worried about Sylvanas’ storyline
Lady Sylvanas Windrunner , also referred to as "the Dark Lady" and "the Banshee Queen" during her rule, as well as "the Banshee" following the Fourth War , is the former Warchief of the Horde and former supreme ruler of the Forsaken , one of the most powerful factions of undead on Azeroth. In life, Sylvanas was the ranger-general of Silvermoon , whose leadership acumen and martial prowess were without equal. Ultimately, however, Sylvanas fell in battle. Rather than honor the ranger-general with a quick death, Arthas ripped out her soul and transformed it into a banshee: a cunning and vengeful agent of the Lich King empowered by hate.
She currently serves as leader of the Forsaken faction of undead and Warchief of the Horde after the Battle on the Broken Shore. She is the middle sister of Alleria and Vereesa Windrunner. After fighting and losing at every turn to his forces, Arthas killed her. In revenge for her stubbornness, he severed her soul from her body, forcing her to serve him and aid him in the destruction of her beloved city. During the time when the Lich King was losing grasp on his undead minions, Sylvanas gained her free will and plotted against him in Lordaeron with the help of the Nathrezim.