Trust me, NO ONE welcomes Sith. My mod involves a rebellion of Dark Jedi against the Empire, following a self-proclaimed Sith Lord. Since these Sith actually announce themselves, they're feared even above the Empire (very few know the Emperor is a Sith). I'm trying to be able to have you able to fight against the Empire, the Rebels, the Pirates, and the Indigenous factions in one campaign... EDIT: Oops, forgot. Also, I'm having the story set so the Emperor makes the public believe it to be an invasion, not a rebellion, so he encourages all systems to fight against these so-called "Sith" and gain the friendship and protection of the Empire. Yet another reason why indigenous groups would fight you.