Nalia has left the party... that leaves me with Anomen and Jaheira for spell casters. I need to kill the demons and thier hoard inj the planar sphere netherworld. I have Monc and Valgy with me too.

Are you inside the sphere?

I don`t think you`ll be able to recruit any new NPC`s in there (I never found any). You`ll have to make do with the ones you got until you get back to your own plane of existence.

Look through your potions, scrolls and magic items. There`s bound to be some stuff there that will be useful in the fight with the demon.