I, Demon Slave

Empusa, an Erinyes, is a creature of passion and lust who must grab the soul of an Earther to serve the demon's war against the Seraphim. The Earther is more than he seems, at times harsh, others gentle. She takes his virginity and easily ensnares his heart. What she didn't count on is the reverse would also come true, waking her long dormant heart to her submissive desires.