I'm working on a data right now so I can prepare to face Demogorgan. With my fight with him before, I found out a few things such as he is immune to a lot of magic (1-6 like daan said), Time Stop and Imprisonment also have no effect on him either. If I remember right, Demogorgan deals out blunt damage when he's not casting spells, so the helm you can acquire from Gromnir would help. Of course, I think daan posted this way back when in the SoA forum too
