The Stars are Dying by Chloe C. Peñaranda

For fans of From Blood & Ash and Shadow & Bone. Star-crossed hearts bleed and the first sparks of war ignite in this dark romantic fantasy loosely inspired by the Greek myth of Astraea and the fall of the Golden Age.

“The brightest star needs the darkest night.”

In a world abandoned by the celestial guardians and left to suffer a tyrant king’s reign, all Astraea knows is safety in seclusion. With fragmented memories of only five years of her life, she’s determined to discover more about her past, even if that means fleeing the cruel arms that hold her safe from the wicked vampires rumored to roam the land.
But when Astraea stumbles upon the mysterious Nyte, she soon realizes determination alone isn’t enough to guard her heart. He lingers like the darkness that expands between the stars, and soon she discovers her captor’s wicked means of control weren’t based on a lie to keep her under locks after all. In her desperation, Astraea accepts Nyte’s help before she can decide if she might have sold her allegiance to one of the bloodthirsty beings the people of her world fear.
Once their bargain is struck, Astraea’s chance to escape comes in the form of accompanying her best friend Cassia to the King’s Central. There on royal territory it’s the centenary of the Libertatem, a succession of trials hosted by the king in which five human lands compete for a cycle of safety from the vampires seeking blood, claiming souls, and savaging after dark. So when tragedy strikes, Astraea must decide if taking the place of a murdered participant for the safety of her kingdom is a ruse is worth dying for, or if protection—and the answers to her past—really are her strongest desires.