Incubus (1966)

Kia is a succubus, luring to their final perdition men who already have sinful habits and libertine inclinations. She tires of this, it's too easy, and these souls are going to Hell anyway. She wants to match wits and charm with someone who is good. So, against the advice of her sister Amael, Kia seeks out Marc, a man who has already faced death with courage. After a night together, Kia finds that not only is Marc's goodness still intact, but she has been ravaged by love. In anger, she and Amael conjure an incubus to deal with Marc. The incubus starts with Marc's sister, Arndis. Who will win the struggle for souls?