Vampire Circus (1972) on Netflix

Count Mitterhaus [Robert Tayman] was a vampire, preying on the children of the town of Stetl. With the death of one more child, the people became sufficiently enraged that they stormed the Count's castle and drove a stake through his heart. With his dying breath, Mitterhaus vowed, "Your children will die to give me back my life." Seven villagers went in, four came out -- Professor Albert Mueller (whose wife Anna had become the Count's willing consort), the Burgermeister, Dr Kersh, and Herr Hauser. Just as the castle is consumed in flames, the Count whispers to Anna, "Tell Emil. He will know what to do."