World of Dragons, Worlds of Mist (Book 3 of The Many Kingdoms series)

Disobeying his parents, a small boy wanders away from home into the craggy unknown of the Coldfire Mountains. Discovered by a family of dragons, he is captured and enslaved as a pet, given the contemptuous nickname of ‘Mik’. When his masters become killers, Mik finds himself reunited with his own people with a heart consumed by rage and guilt.
With vengeance in his heart, and a group of new companions, Mik journeys back to the land of his slavery only to find salvation and love where once was pain and hatred.