I haven't played that game, but it reminds me of a problem I had in the last rooms of Neverwinter Nights. There are these rooms where you have to fight so many powerful multiple opponents that even my 20th-level paladin and his companion couldn't get past at first without getting killed. I finally managed to do it by getting them to chase me through a door into a narrow passageway, so that way there was only enough room for one to come at me at a time. Sometimes I could trick one into coming through the door and then close it so the other one couldn't get through; then I'd only have to fight one. I'd kill that one, rest up to heal myself back to full hp, then open the door again and draw the next one out. Don't know if that'll help or not with the RotK game, but FWIW.
Meant to ping you on my last post.
That works with Aragorn in a few places on Path Of The Dead level.