The Curse of the Ebon Maw by A. S. Raithe

In the space between spaces, an evil so ancient even the gods have forgotten it stirs. All that stands between it and oblivion are a clumsy knight, a displaced duchess, an outcast priest, and a hermit that would rather be a cat. Together with their allies, they alone can stop this long forgotten demon, and defend the world against ever growing threats.