I think its a bummer but I think you need nalia in your party for this to start, so it would probably help if shes in your party when you take the keep.and keep her in the party until all this happens. Besides, she can get you alot of XP by learning spells. after shes learned all the spells she can and her lil side quests are over--------- dump her.
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THERE CAN BE ONLY ONE!!!!!!!!!!!