Frontir (Poslednyaya Zhizn' Kniga 2)

No one knows for certain what caused the Shadow to come into existence. Clerics say it was the gods laying a curse upon this world. Philosophers maintain that the Shadow of Strix is nothing short of a blessing and new milestone in human progress. But both sides agree that the Shadow will eventually swallow up this world and change it beyond recognition.
However, there are also the mages, and they think the whole debate is just so much hot air. They accept the Shadow as is with all its horrors and wonders. Furthermore, for the last several centuries, mages have risked their lives attempting to harness the Shadow's Power for themselves.
Unsurprisingly, only a select few have access to knowledge about the Shadow's magic. Max Renard understands that, so he chooses a different and more hazardous path. He decides to head for the frontier himself to experience the Shadow's Power firsthand.