1986 animated film by Jiří Tyller

Krabat, a beggar boy, is lured to become an apprentice to an evil, one-eyed sorcerer. With a number of other boys, he works at the sorcerer's mill while learning black magic. Every Christmas one of the boys has to face the master in a magical duel, where the boy never stands a chance because the master is the only person who is allowed to use a secret spell: The Koraktor.