I'm doing some writing, and the main character is to be a nymph. A Hyleoroi to be specific, basically a forest Lady, who unlike dryads are not beholden to any one place.
True fey creatures in this setting are angels that remained neutral in the conflict between heaven and hell. They were thus abandoned to the world where they took new shapes, genders, etc.
This nymph is basically a fertility spirit. Not one of birth, but of sexuality.
She has the power to release powerful pheromones, which she controls the level of. If in danger, and it be a male, she can make it so powerful that the sudden overpowering lust and blood pressure cause heart attacks and aneurisms. So basically she may use desire to charm and as a weapon.
What else might a literal spirit of sex be capable of? We're not talking succubus here btw. Not interested in BDSM here.
Also, what might a man who has captured and tricked her into being permanently bonded to him gain from her influence and satisfaction of needs beyond most, if any, mortal women?