First of all a warm welcome to the forum
Have you a save game from before entering the Hall of Echoes?
Level 30 seems to me a little bit low ? ..
(I was at least level 34 when I first entered the Hall of Echoes)
But you can try this:
First summon your creature or another summoned ally (Ghost, undead or Demon), then use Hide in Shadows (1 point is already very useful) and run to Sassan with a melee weapon!
Enemies who use in the first place magic or a bow are weaker with a melee weapon.
And if you have free skillpoints or already invested in the skill "Charm" (or Blind), give it a go and Charm (or Blind) one of the soldiers who's helping Sassan ! This can fast change a battle
