Elven Blood by Devon Vesper

Their kind has hated one another from the very beginning. Could mixing their blood save their world, or will it destroy them all?

Powered by hate and madness, the Architect is determined to destroy the Twilight and all those within it at any cost. Seven years ago, two brave heroes put a temporary stop to his plans, but it’s only a matter of time until their stopgap breaks and everything comes crashing down for good. And when it does, countless species will lose their lives. The time has come to answer the call of fate.
On his way to join the quest to save his world, Twilight Crown Prince Cervayn is mortally wounded. Chasing the Architect brings the King of the Fold to Cervayn’s side but, to save him, he must turn Cervayn into a vampir—the very thing elves have been hunting for millennia. It was always known to be impossible to turn elves into vampir, but it’s a risk he has to take. But taking time to learn about his new nature means Cervayn’s friends are scrambling without his help even as he finds himself in the middle of a civil war caused by his very existence.
Running out of time to complete the mission, Cervayn finds himself torn between his duty to his kingdom, the love of his friends, and an unexpected connection to the Prince of the Fold. It’s going to take every last vampir and elf on the team to save the Twilight, but with the Architect doing everything he can to break them, there might not be enough of them left to even try.