Originally posted by NewGuy01
Not to be DLOTS; he (apparently) took him as a disciple for a while and left him to rule Medriaas. He was never said to have approached him again, and it's implied that he (and the other AS) weren't supportive of his actions thereafter.
It's interesting that Freedon Nadd(in his final moments) claimed that Kun was a pretender and that the future of Sith lies with Satal and Aleema.
Well, I scanned Vitiate's respect thread to see if there was anything, and whilst this isn't the source I had in mind, it'll do:
Nathema: Once known as Medriaas, Nathema was an agriworld of the Sith Empire at a time when Sith also controlled the Chorlian sector. An ancient Dark Lord of the Sith named Darth Vitiate destroyed all life on Nathema with a ritual designed to grant him immortality. A transcription of this ritual was recorded by Darth Revan and served as the inspiration for Lord Kaan's thought bomb on Ruusan.-- Force & Destiny: Core Rulebook
Pretty sure Force and Destiny is in-universe or from a limited narrator, hence the Darth Vitiate.
Alternatively, Vitiate could have created the title himself, since the first people who have it are Revan/Malak and then his own Sith Empire.
Andeddu is a possible exception, but there's no date on his life so it could have taken place after Revan/Malak were a thing.