Magician

He held the fate of two worlds in his hands...
Once he was an orphan called Pug, apprenticed to a sorcerer of the enchanted land of Midkemia.. Then he was captured and enslaved by the Tsurani, a strange, warlike race of invaders from another world.
There, in the exotic Empire of Kelewan, he earned a new name--Milamber. He learned to tame the unnimagined powers that lay withing him. And he took his place in an ancient struggle against an evil Enemy older than time itself.
From the Paperback edition.