Zelashiel

Zelashiel, also referred to as Zelashiel the Blasphemer, was a Force-sensitive individual who wielded the dark side of the Force. One of the Force techniques that Zelashiel was proficient in was the ability to drain an individual's essence, a delicate procedure that was exceedingly difficult to use in combat. Zelashiel's teachings eventually were detailed in the Sith Holocron of the Dark Lord of the Sith Darth Revan around the time of the Jedi Civil War.

Sometime between 1000 BBY and 980 BBY, Zelashiel's instructions were commented on in an essay authored by the Sith Lord Darth Bane, who had studied Revan's holocron before destroying it. Many years later, Bane's essay, including his notes on Zelashiel, was added to the Book of Sith, a compilation of historical writings collected in one volume by Darth Sidious.

Text and facts from the “Zelashiel” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.