After Dark by K. L. Thorne

When his commander fails to return after being ambushed by the faerie king, Raxx, an elusive shadow demon, is sent out to locate the missing soldiers.
Instead of his fellow demons, Raxx stumbles upon far more than expected: Faye Goldwyrm, the faerie king’s youngest daughter, and she’s on her own mission to bring her runaway sister home.
The two soon realise that they will have to put aside their differences and work together if there is to be a chance of success.
As tensions build, so does the mystical curiosity Raxx and Faye feel for one another. Even more curious is the fact that whenever they touch, the sparks literally start flying…