The Banneret — Duncan M. Hamilton

Demons have been hunted to the verge of extinction. Those who know of the horrors lurking in the dark act as though the threat is long past. It has allowed Conrad to continue his education undisturbed, to work toward joining his friends as a comrade-in-arms rather than a child to be protected.The appearance of two powerful demons changes everything. The creatures are back, stronger than ever, and the years of quiet are at an end. The Principality finds itself in need of demon hunters once again. Conrad and his comrades are the ones for the job.The chain of clues draws them ever closer to what their unseen enemy desires, and they find themselves in a deadly race to stop it from regaining its former power.