Demon from the Wasteland. Sorcerer of the Russian Empire

The third book about the investigations of Count Averin.
After the battle with the Imperial demon Kuzya, sacrificing himself, he ends up in the Wasteland — the Ice Desert, where demons reside. Count Averin does not know if he is alive, but he intends to open a corridor to the world of demons and try to save his friend at any cost. It is believed that a person who enters there perishes immediately. But is it really so?
The studies of the Wasteland have been classified, and yet this is Count Averin's only hope. With the help of friends and the future Empress Princess Sofia, he takes a risky step. But even if their plan works, who knows what other demons might escape from there — and what it will mean for the world.