Putting a ruler on a throne turns out to be a very thankless job. Everyone is just itching to pull some trick on you—say, sticking a magical dagger in your back. Of course, for the sake of some "state necessity," naturally it can be nothing else.
But the traitors didn’t take into account all the possibilities of Oleg—once a cheerful student from our world, and now a powerful demon-necromancer. And his friends—lichs and vampires—absolutely don’t agree that he should go to the realm of the dead after such nonsense. So Oleg had to scramble out of the grave as quickly as possible to restore justice.
And when a demon-necromancer, with all his enthusiasm, starts restoring justice, people around him very soon realize that the old Latin proverb "Let the world fall, but let justice prevail" can sometimes be taken literally!