The Divine Shallows by Alexandra M. Tran

In this enchanting epic fantasy romance debut, two fey sisters are bound by both blood and love, but separated by divine privilege. In the mythical realms of Neramyr, achieving divinity as a warlock or sorceress is to be differentiated as a god among gods where magic is the governing constant.

To possess the moon’s markings is to wield her divine power. Every seventh year, a new septet of divine warlocks and sorceresses is chosen by the Moon Goddess. To ascend from the mundane to the exceptional, two things must be achieved: bear the moon’s Mark and complete her divine trial.
Daughter to one of the fey’s strongest bloodlines, Elyria’s very existence has defied the tradition, pride, and faith that guided her folk for generations. Forsaken by the Moon Goddess upon her birth, Elyria is refused the divine marking. Condemned to a life of discrimination and hostility, Elyria longs to triumph over her tainted past.
Born to the same bloodline, Elowyn bears the moon’s Mark and is fated to inherit the throne—a title that was once Elyria’s birthright. For Elowyn, queendom is a burden she was appointed, but never desired. One day, fate shifts when the Moon Goddess unexpectedly offers Elyria a chance to face her divine trial—an opportunity an unmarked fey has never been granted before.

As Elyria and Elowyn embark on their separate, yet interwoven journeys, they uncover unsettling truths about the ancient realms of Neramyr. Secrets unravel, tradition is challenged, love is tested, and the course of destiny is rewritten.