whats best is to wander you mage over to a group of enemnys(with appropirate protection,of course) concealing him with invisability, and then cast SUNFIRE, which hits for 1d6 per level culminateing in a MASSIVE 15d6 save vs. spell for 1/2. Delayed blast fireballs are also good, and so is chain lightening as even though it afffects all enemys in 30 ft it doesnt hurt your own party.
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