Demon An infernal being that seeks to corrupt the virtuous or tear down the righteous is called a demon. As an example, a Succubus is a demon that seeks to seduce a righteous knight into betraying his oath of chastity.
Devil An infernal being that seeks to induce vice is called a devil. An Erinyes that seduces a family man and keeps him from providing for his family would be archetypal diabolic behavior.