Hiraeth - The Fae Queen's Court, #3

War has come for the fae. When Owen Williams became a vampire, the world as he knew it shattered. The fae and the United States militaries are fighting in city streets and he is helpless to stop it. As Beira and her generals deal with the war's rapid escalation, Owen is sent back to Tearmann to deal with the flood of refugees that now call it home. But despite months of training from Beira, Owen still struggles to control his burgeoning vampiric abilities and the hordes of terrified fae in Tearmann threaten to overwhelm him.
Then Merlin, the enigmatic resident of Avalon, offers to teach Owen to manage his powers in ways Beira couldn't. But he has an agenda of his own and he wants Owen's help in exchange for his knowledge. After all, the halls of Avalon are in ruins. The beings that walked those halls are gone. If they were restored, Merlin might be able to stop the endless Changes that terrify the humans so much. They could bring peace to the beleaguered fae.
or awaken things hidden deep within Avalon and lead them into a war worse than ever before.