The Dark Hand of Magic by Barbara Hambly
Book 3 of 3: The Sun Wolf and Starhawk
 
Sun Wolf knew he had the power of magic, but he needed a master wizard to teach him to fully use his skills. But there was no one who could do the job. When he was called upon to help old friends against the ancient wizard, he did - thus ensuring a curse that would be executed, unless Sun Wolf could harness his own powers and find a way out....
 
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