Blood Oath. The Last Immortal, #51

Nicholas has survived centuries of darkness, but nothing prepares him for the strange crimson mark that suddenly appears on his chest. When Victorius reveals that he carries the same mark, Nicholas discovers that their lives are connected by an ancient blood oath created by the first vampire bloodline. If one dies, the other may follow. Worse, the powerful Crimson Court believes their bond could become the key to controlling the oldest vampire blood magic.
But the truth is far more complicated. The original blood oath was never meant to be a curse. It was created as an expression of love and freedom by two vampires who wanted to choose each other beyond death. Over generations, their promise was corrupted into a weapon used to control vampire bloodlines. As Nicholas and Victorius uncover the history behind the covenant, their own relationship becomes increasingly difficult to separate from the magic surrounding them.
Attraction, hunger, fear, jealousy, and trust force them to question whether their feelings are truly their own. When the Crimson Court captures Victorius and attempts to turn their bond into the foundation of a new vampire dynasty, Nicholas refuses to abandon him. Together, they uncover a forgotten path to freedom-one that demands neither sacrifice nor submission. But breaking the blood oath comes at a price.
They may lose the immortality they once believed was eternal. They may have to face a future where time can finally touch them. And they must learn that redemption is not punishment, love is not possession, and blood cannot decide who belongs together. In the final confrontation, Nicholas and Victorius must choose each other without magic forcing their hands. Because their love can only become truly powerful when they are free to walk away-and choose to stay.