If you have a warrior character, have them melee Samuel, but they will need a high accuracy in order to hit him frequently. A good sharpened weapon can do nice damage to Samuel. My warrior also had high shield blocking skills, so Samuel rarely hit him(except for the spells). If your warrior has a high resistance, that will limit the damage that Samuel does with his spells. It also doesn't hurt to have a few healing potions as well.
If your other character is a archer/wizard, put them in sneaking mode, and position them away from Samuel. This way, Samuel will not attack the archer/wizard, nor will Samuel's area effect spells affect the wizard/archer. The archer/wizard will be free to unload with spells or arrows without any chance of harm or having their attacks interrupted by Samuel.
I fought and killed Samuel using my PC as a warrior, and the DK as an archer. If you have a wizard, use the hammer spell to soften up old Samuel.
Good luck! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
