Nazareno Cruz and the Wolf(1975)

Overview

Nazareno Cruz is the seventh son of a couple living in a high mountain village. According to a myth, a seventh son will become a wolf on nights of the full moon but this doesn't occur to him. When he's older, he meets the Devil, who offers him the wealth of the world if he turns his back on his newfound love, but if he refuses, he'll become a wolf.