Blood Betrayal — Tessa Dawn

Fantastic! 
"Wow! {Blood Betrayal} is a page-turner, held me gripped from start to finish. Gritty, hard-hitting, but ultimately a story of true love that never gives up...fantastic!" ~ Carole Mortimer (USA Today Bestselling Author; #1 Amazon Bestselling Author; 2017 RT Career Achievement Award; 2015 RWA Nora Roberts Lifetime Achievement Award; over 225 books -- Regency, Contemporary, and Paranormal)

Back Blurb 
Saxson Olaru is one of the select, the few, the elite...

As a ruthless sentinel sworn to protect the ancient Vampyr king and the house of Jadon, he has "HOJ" literally inscribed on his heart: a heart that was tragically broken centuries earlier, when human hunters slayed his mother and Dark Ones murdered his father. Having survived the unthinkable, he never dreamed he would come this close to another human predator, let alone a female pretending to be his destiny.

Kiera and Kyla Sparrow are twin sisters: humans, living very different lives. While Kiera is selfless, clever, and talented, Kyla is dark, duplicitous, and damaged--she belongs to a secret society of vampire-hunters, and she has sworn to destroy as many as she can.
  
When Saxson's Blood Moon appears in a February sky, and the matching constellation, Cetus the Sea Monster, appears on Kiera's wrist, Kyla knows exactly what it means: The celestial gods have chosen her beautiful sister to be the eternal mate of an immortal vampire--she just doesn't know which one.

And it really doesn't matter.

If Kyla can recreate the sacred emblem on her own inner wrist, she can take Kiera's place and commit the ultimate Blood Betrayal.
  
When duty, obedience, and honor clash with a deep, gnawing intuition, an honor-bound warrior will be forced to choose between allegiance to the house he loves and the quiet voice within, whispering: "Warning!"  
 
One wrong move.
One wrong choice.
And all will be lost forever.  

Discover the "Extraordinary Storytelling Talents" of Tessa Dawn in her breathtaking, original saga: the Blood Curse Series (Quote by Midwest Book Review)

Also by Tessa...

Blood Curse Series
Blood Genesis, prequel
Blood Destiny, 1
Blood Awakening, 2
Blood Possession, 3
Blood Shadows, 4
Blood Redemption, 5
Blood Father, 6
Blood Vengeance, 7
Blood Betrayal, 8 
Blood Ecstasy, 9
Christmas In Dark Moon Vale (Coming)

Pantheon of Dragons
Zanaikeyros - Son of Dragons, 1
Axeviathon - Son of Dragons (Coming)

Dragons Realm Saga
Dragons Realm, 1
Dragons Reign (Coming)

Daywalker - The Beginning