The Unworthy King by Maggie McCallum
Nora is an American graduate student living in Ireland when the existence of the vicious Fae is revealed. According to the President, the Fae have been living amongst the humans for years, stealing their businesses, their money, their babies, and even their minds. After the humans declare a war of extermination, Nora must pick a side. The only problem? Her new boyfriend, Rian, is the reluctant Fae King. The passion of their romance is matched only by the stakes of the war. Stepping through a fairy ring for the first time, with Rian by her side, Nora uncovers the truth about why Rian only has four fingers on his left hand and what that means for the Fae people. As Rian grapples with regaining the trust of the Fae, Nora discovers that the Fae are more like the humans than anyone realizes. She must help Rian discover his Worthiness, as well as her own, or all hope is lost.