Courting Nightfall by Amanda Meuwissen

Zen is a darkling — half human, half dark elf — in a world that hates him, protected only by having been raised by the Order of the Sun to become a priest. He continues to fail to rise above being an acolyte despite having come of age and longs for a different life, one he only glimpses in dreams when he is with a mysterious, beautiful man he wishes was real.

After encountering an adventuring party made up entirely of other half-races, Zen is drawn to accompany them on their quest to find and destroy a fabled vampire lord. However, the pull he feels toward those lands might be more fated than he realizes.