Gamemaster is a science-fantasy novel by Nikolay Sobinin, the first book in the eponymous cycle, genre: LitRPG, action fantasy.
Oleg is a former hardcore player, and now a sought-after gamemaster for a variety of VR projects. Somehow, he gets drawn into the intrigues of a mysterious state corporation. One day he discovers that he’s inside an incredibly realistic virtual reality presented as a role-playing game in an atmosphere of pagan Rus—and he has no idea how he ended up there. Trying to remember soon leads him to realize that the reality surrounding him is nothing like what it tries to seem at first glance.