Never Leave Your Monastery by H.G. Potter

The monks raised Jacob to defend the Monastery of Whitehammer with a quarterstaff. Now coming of age, he wants to find out about living in the outer world. Having escaped to the wilderness, a group of elf-blooded mountaineers, “the valraphs,” capture him. They speak of something in the north, and an ancient evil, a powerful Banelord, Nimrul, aka “Professor Naza” seducing the kingdoms. Jacob returns, a prodigal, but has a message: only repentance of the monks can deliver the kingdoms. Accused of Sorcery, he must prove his innocence, he and his companions go against the Dire of Melancholy!