Hey Obi-Wan - raise undead would also work if you have high level clerics... but as usual, Accord is on the money with sending minions in - after all, those beholders and such do serious damage.
You can send a tank if he is hasted, perhaps. Depending on your party... another thought would be a few fireballs in the vicinity.
Good luck!
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Defender for the Light -
Goodness knows there is a lot of Dark out there!! - Where are my matches?
Wandering Joke of the Laughing Hyenas