So I played KOTOR 1 and 2, and I never remember a definitive statement acknowledging Ajunta Pall as thee first Sith Lord. I remember him saying he was one of the first, and I thought of him as one of the first Generals, much like General Xendor. But in the Codex for the Tomb of Ajunta Pall it definitively states that Ajunta Pall was in fact thee first Sith Lord. But if memory serves me I thought George Lucas didn't want the first Sith Lord named, much in the same way he doesn't want that Jedi Loser Yoda's species named.
So I don't know how I feel about Ajunta Pall being thee first Sith Lord. In KOTOR Ajunta Pall expresses regret for leaving the Jedi Order, no true Sith would be so weak, especially the father of the Sith. So I say we reject Ajunta Pall and call him a decoy for the true first Sith Lord, because the true first Sith Lord has some sort of plan maybe. He is going to come back through his blood line, the sun turns black, all that stuff, and doesn't want the Jedi Order to discover his dealings in death, so a decoy is needed. That's my two cents.
"Execute Order 66"
Austin-
TK-1649 (501st Legion, Mountain Garrison)
Athazoth-
Sith Marauder lvl 10 (Guild: Dark Prophesy, Server: Space Slug)