Edge Lines by Ava Marie Salinger

The Gods have come to San Francisco…

Cassius Black and Morgan King’s trip to Ivory Peaks to uncover clues about their past takes an unexpected turn when a rift materializes and war demons attack the capital. Having saved one world by the skin of their teeth, they return to Earth, only to find it has been rocked by ominous quakes bearing a close resemblance to the phenomenon that nearly destroyed the Dryad kingdom.
After defeating demons that emerge from a crevasse in San Francisco, Cassius and Morgan rescue the Wild God Pan from the bottom of a rift with the help of Victor Sloan and the city’s otherwordly. But instead of thanking them, Pan makes a startling demand: rescue his lover and prevent the Spirit Realm from being destroyed, and he will reveal the truth about who Cassius and Morgan are.
Help comes from an unexpected source when a pair of Reapers visit the city and Cassius, Morgan, and Victor soon go hunting for a missing deity who may hold the key to saving all the realms. Can they free the immortals from their prisons and find the powerful artefact that can bend the mind and will of even a God? Or will the enemy who has long manipulated them from the shadows win this war and destroy everything they have come to care for?