The Memoirs of a Faun by Caldon Mull
The story itself, is of a unique group called the Numinous Constraint Agency. It is their job to recover Numinosities living in our world who are in moving into their Luminous Cycling. Cycling can be a very dangerous time for mortals in contact with them and the world we inhabit could be destroyed if they’re left to run the gauntlet alone and unencumbered. The Numinous Constraint team, consists of an Angel, a Titan, a human agent from the CIA, and the boss, Arteus, the Faun.