Claim My Soul (Monsters of New York Book 6) by Laura M. Baird

An unlikely alliance reveals a destined fate... Herleif Aganarsson is a troll competing in the underground shifter fight club in New York City. Alexia Stavros guides the souls of fallen warriors to the afterlife. Their initial meeting results in confrontation, so when they’re tasked to work together against an evil foe, a partnership seems unlikely. But when respects grows and passion flares, their bond is undeniable. Will these two complete their mission without losing their own souls in the process?