Blood Sabbath (1972)

A young man named David unknowingly ventures into a land controlled by the powerful witch queen, Alotta, and her coven. Every year the local villagers must offer a child to the queen in order to maintain a pact of peace. But David has fallen in love with a river nymph named Yyala and he cannot have a relationship with her as long as he has a soul. So, he offers his soul to Alotta in exchange for the life of a sacrificial child. Now David and Yyala can be together, but if Yyala ever abandons him, his life belongs to the witch...