Yeah it's strange that every badguy has to have this kind of special name , but then again it sounds so much cooler if they do have meaning . Can't wait to see Darth Patrick in kotor 3 a super uber Sith lord from beyond the void of space .
But if you look at Sion or kreia they use their normal names even Malak doesn't change his name or bears some sort of title . ANakin becomes Darth Vader and Palpatine changes to Sidious ... strange guess that some of the sith have bigger ego's and choose a new "name" ( title ) but others don't , anyway who gives them their names and well aknowledge it . You know , you can't declare yourself lord or king , emporer before the people in general agree that you are indeed worthy to be such ( wow heavy stuff , guess I think to much . And call you so .
Anyway seems like Malak wasn't that bigheaded like nihilius ( can't be his real name , I think it's Ferdinand