What about this bit from the star wars wiki:
That kind of makes it sound like other Sith put an actual stamp of approval on the whole thing.A group of ancient Sith spirits, led by Marka Ragnos, declared both Kun and Qel-Droma the leaders of the new Sith Empire. Exar, the more powerful of the two, was appointed the Dark Lord of the Sith, with Ulic as his Sith apprentice, and both were anointed with unknown Sith symbols on their foreheads. With this resolution of the leadership dispute, the Great Sith War had brutally begun.