Sovereign

Humanity survives behind rows of towering crosses, clinging to life while the wasteland beyond crawls with drudges-vampire‑zombie creatures born during the world's collapse. The Catholic Church stands as the last bastion of hope, its holy knights battling the darkness and its white‑clad Angels using rare empathic gifts to help the broken.

Kayla is the strongest Angel alive... which makes her the perfect target.

When she is kidnapped by a Blue Blood-an elite, beautiful, and monstrous vampire marked in distinctive tattoos-her fate seems sealed. Until she is rescued by a stranger who should not exist.
Tempest Glaive, the Sovereign Vampire, has wandered the wasteland for two thousand years, hunting the very creatures he was cursed to rule. Once the legendary commander of the holy knights, now the most feared vampire alive, he despises what he has become. Saving Kayla was never part of his mission.

Loving her was unthinkable.

But when they return to the Vatican City, they find it infiltrated by Blue Bloods. Angels have been stolen and the pope murdered. The sanctuary of humanity is crumbling from within-Kayla and Tempest are the only ones who can stop the coming slaughter.

To save the last human stronghold, they must fight side by side against enemies wearing familiar faces. To stay together, they must defy a world that forbids their love.

And as darkness rises, one truth becomes impossible to ignore:

The greatest threat to the world may not be the monsters outside the walls...
but the forbidden bond growing between an Angel and the vampire king who was never meant to love her.