Half-Blood Book by Jennifer L. Armentrout

The Hematoi descend from the unions of gods and mortals, and the children of two Hematoi-pure-bloods-have godlike powers. Children of Hematoi and mortals-well, not so much. Half-bloods only have two options: become trained Sentinels who hunt and kill daimons or become servants in the homes of the pures.Seventeen-year-old Alexandria would rather risk her life fighting than waste it scrubbing toilets, but she may end up slumming it anyway. There are several rules that students at the Covenant must follow. Alex has problems with them all, but especially rule #1:Relationships between pures and halfs are forbidden.Unfortunately, she’s crushing hard on the totally hot pure-blood Aiden. But falling for Aiden isn’t her biggest problem–staying alive long enough to graduate the Covenant and become a Sentinel is. If she fails in her duty, she faces a future worse than death or slavery: being turned into a daimon, and being hunted by Aiden. And that would kind of suck.