Throne of Shadow and Soul
Urban Fantasy Thriller: Magic, Supernatural Powers, Occult, and Supernatural Conflicts in Veritas; Aether & Umbra Balance, Keystone Prophecy, Series Finale.

In the fractured city of Aethelburg, a rigid order of light-wielders, the Lumina, reigns from gleaming spires while crushing the shadow-wielding Umbral in the grimy warrens below. For Molly White, an orphan of the dark, survival is a daily battle fought with forbidden power. For Argent Guard Captain Dylan Hodges, she is a heretic to be purged. They are enemies, bound by a history of hatred and a thousand-year-old lie.
But when a magical explosion leaves Dylan tainted by the very shadow-magic he despises, his world of black and white shatters. He can suddenly see both Lux and Nox—the light and the darkness—and with this terrible new sight comes a horrifying revelation. A fanatical leader is preparing a "purification" ritual that won't cleanse the city, but annihilate it. An ancient prophecy speaks of a Fulcrum, a power to unite both forces, and it points not to one savior, but to two mortal enemies.
To save their city, Molly and Dylan must forge an impossible alliance. Plunged into a desperate race against time, they are hunted by Dylan’s own father and a legion of zealots. Their only hope lies in mastering their combined powers and confronting a catastrophic storm of uncontrolled magic that was once Molly’s dearest friend. They must become the balance their world has forgotten, or be the final witnesses to its oblivion.