Micah Grey trilogy

Gene, the daughter of a noble family, runs away from the decadence of court to R.H. Ragona's circus of magic, where she meets runaway Micah, whose blood could unlock the mysteries of the world of Ellada.

Micah's powers force him to turn to the untrustworthy Dr. Pozzi, as anti-royalist unrest threatens Ellada, and an ancient sect that once nearly destroyed the world reappears to spread terror when the Chimaera reveal they still exist.