It's useless to fight Rosh until Tweedle-Dee and Tweedle-Dum are out of the picture. If you read the icarus scripts under base\scripts\vjun3
, Rosh is set as "invincible" until the twins are killed.
I've played through the game as both a light and dark jedi, and Vjun is one of the toughest if you are a dark-force user. But it's certainly not impossible. Without Force Absorb, the Twins will give you hell, because their lightning attacks can immobilize you if you're very close to them.
I've found the key is to keep your distance, and keep force-pushing them until they fall, then just use your saber-throw to finish them off. You can also hack away at them freely whenever they stop to "heal" Rosh.
made a superb point about using guns. I'll have to try that. I'm a little skeptical because force users can always reflect any projectile weapons with force-push (thermals, cuncussion rifle, rocket launcher, repeater alt-fire, flechette alt-fire) and dodge the rest (blasters, disruptor, etc.). Also, if you switch to guns, you're wide open for Rosh's saber attacks. He uses strong style only (check out the base\ext_data\npcs\rosh_penin.npc
file) and will take you out quickly, especially if you're playing at Jedi Master difficulty. That's if the Twins don't yank the weapon from your hands first...