" A vergeance in the Force existed there—a nexus of power and energy that could be put to many uses, both worthy and wicked. Vergeances rose of their own accord; they could not be created, only discovered. In the far distant past of the Old Republic, back during the ancient Sith Empire, Sith and Jedi had often warred for control of these vergeances. The Sith had held this one first. "

― Claudia Gray , Into the Dark (Star Wars: The High Republic)