The Luminary - The Brennan Coven, #1

A witch running from death. A warrior seeking redemption. Only one can win a battle that may very well cost them their hearts and strip them of their souls. When Meera Brennan learns she's a Luminary, one of the most powerful witches in existence, it rocks her already fragile world. The revelation explains the disturbing episodes that made her question her sanity, but does little to soothe the sting of discovering her life is now at risk.
To save herself and keep peace within the veiled community, Meera will have to hone her powers and brave an ancient realm to destroy the slayer's magickal source. She alone must dispel chaos and ensure the balance of good and evil for all mankind. Banished and stripped of his guardian powers because of a witch, Ghanem Adamo, former prince of the Saharren realm, receives a chance at redemption when his estranged father reveals an immortal battle destined to alter all realms.
In order to protect the innocent, regain his title and reunite with his family, Ghanem must destroy the slayers' source of power and bring down their terrorizing leader. Her life .