Magnus was a title claimed by self-anointed rulers of the most ancient Sith. It could be translated as "All-Powerful," "Lord of Lords," or "Emperor." Darth Malak, who reigned as a Dark Lord of the Sith during the Jedi Civil War, was referred to as a "Sith Magnus."
During the Clone Wars, a genetic terrorist unaffiliated with the Sith took the alias of "Zeta Magnus" to throw the Jedi Order off the scent and to subtly mock Darth Sidious, the legitimate Dark Lord of the Sith. It worked to an extent, as the Jedi Apprentice Halagad Ventor mistakenly suspected that the genetic terrorist might have ties with the Sith of old.
The title of Magnus was created by Abel G. Peña for the Knights of the Old Republic Campaign Guide in 2008. However, the guide did not elaborate on its meaning. Upon being asked about it, Peña himself stated in 2011 that he could not yet give a precise answer to that question. In 2015, however, the title reappeared in the eNovella SkyeWalkers: A Clone Wars Story, in which Peña finally explained the origin and meaning of Magnus.
- Knights of the Old Republic Campaign Guide