Well, it depends on what are your basis for gameplay... Edwin is powerful yes. He also has this wicked sense of humor. Next he is the best mage in the game. But then, if you are story wise and RPG wise instead of powergaming, or rather you want a versatile player, it has to be Aerie. I find her the most versatile character next to Jaheira I suppose...
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Chaotic Cavalier of ALSB, protector of the Innocent, slayer of the mad...