Steel And Promise by Alexa Black

Courtesan Cailyn Derys serves the passions of the noble classes—but she’s never served anyone like Teran Nivrai. Everyone whispers about the reclusive noblewoman, indulging her penchant for cruel passions on a private, hidden planet. She’s even modified her body with retractable steel claws. Drawn by curiosity, Cailyn can’t resist a meeting. Is Lady Nivrai the demon everyone whispers about, or have gossip and scandal made a monster of her?

Sex and pain draw Cailyn in, but the loneliness Cailyn sees in everyone’s favorite villain keeps her there. When the ruling Councils decide to use Teran’s gift for inflicting pain—and her claws—against their enemies, will Cailyn discover that the monster is real?