Night Seeker - City of Crows, #9

Calvin Kinsey has always had terrible luck. But this time, his bad fortune might cost him everything. In the wake of a successful raid on his mortal enemies, the Children of Enoch, Cal Kinsey unwittingly binds himself to a critically damaged seraph blade. With every minute that passes, the broken blade drains more of his life force. And the only way to stop the blade from devouring him is to destroy it-at the same place it was created.
Accompanied by his mysterious seraph father, Cal must venture deep into the Eververse and overcome dangerous threats in its many strange, unearthly realms. Worse yet, the fallen angels who command the Children of Enoch want the blade so they can use it for their awful ends, and they'll wreak whatever havoc necessary to steal it back from Cal. Worlds away from all his friends and everything familiar, Cal will have to fight his way through the most difficult trial of his life.
Even if he succeeds, he might be forever changed. But if he fails, he'll cease to exist altogether. Night Seeker is the ninth novel in the action-packed City of Crows urban fantasy series.