Oath of Betrayal by Olena Nikitin

She was broken, but even a shattered blade can kill…

Tormented by grief and powerless after the loss of the men who anchored her magic, Annika fakes her death, seeking refuge in a secluded town. For years, she hides her identity until a chance encounter with a dragon exposes her unique power to the Lord Commander of the Dragon Riders.
Even though she escapes, a yearning for a soul-deep connection with the magnificent beast haunts her dreams. When the commander tracks her down, his touch rekindles her crippled magic making her question all she knows.
He claims she is his ultimate weapon and plans to bond her to his dark fae necromancer—but Annika is done being controlled.
When vampiric ghosts attack, she takes fate into her own hands, choosing to bind herself to the dragon.
Hunted by the Lich King and torn between the commander, who ignites her magic, and the necromancer, who tames its roaring inferno, Annika forges herself into the weapon she was destined to be.

However, the dragon’s anchor is not enough when impending war and betrayal sets her world ablaze.
Even if she sacrifices her soul to take another, can one conduit mage save a failing kingdom?