Warbound. Children Of The Merge, #1

The miracle saved two realms, destroyed her world. At ten years old, Simone Wells was the key to a divine reunion, wielding the power of the Oloru to stitch Earth back to its lost twin realm, Bani Ala. The spell was a triumph that reshaped existence-but it cost Simone her parents and her childhood, leaving her a savior in a world she no longer recognized. Fifteen years later, the miracle is rotting.
The continent of Sundira is a patchwork of war-torn ruins and collapsing kingdoms. Simone survives as a reluctant weapon, wandering the fringes of a world she helped create, haunted by the price of her power. But when a simple escort mission for a desperate mother and son pulls her into the center of a brewing apocalypse, Simone can no longer run. Monstrous shadows stalk the Great Houses, and an unseen force is driving humanity toward total annihilation.
As ancient alliances crumble and the gods remain deaf to the screams of the dying, Simone must face a harrowing truth: saving the world once wasn't enough. The war for the soul of the world has begun.