Im pretty sure you can though they may bring down your xp if its to high. Wont be able to import it in to other games besides throne of bhaal unless you count neverwinter nights which will take you down to level 1 and take away your items and if your stats are determined to be to good to be obtained from their point buy system they will strip those down too. Hell your not even guaranteed to keep your class or portait but HEY! you can keep your characters name WOOHOO!
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BOW TO THE BISCUIT KING AND HIS THRONE OF SCONE!!!