KOTOR II. The protagonist seems to be some sort of Chosen One and KOTOR II introduced the "true Sith" nonsense (have mercy on me, Imperialscum) and lots of nonsensical philosophy.
I also hate KOTOR's timeline placement. If you're don't want to connect to TOTJ, don't set the story near TOTJ. KOTOR could have been set during the New Sith Wars.