Hellbound (Bound Duology Book 1)

Throne of Glass meets The Mindf*ck series in a dark, slow-burn romantasy where a bladesmith enters the king's deadly trials to become his next spymaster, forced to partner with the bastard prince to hunt down a serial killer. Except... she IS the killer and the king is her next target. Can the prince catch her? Let him try. She kind of likes it.