The fear that Samael had instilled in them was enough to last a lifetime. With having an option of death or acknowledging the new emperor, everyone had no choice but to choose the latter willingly. Yes, willingly... if that was even what it was called.
Samael ascended the throne with no problem after that and even mobilized more nobles to contribute to the empire. Of course, their contribution was all due to fear of the devil breathing down their neck.
A different approach from the previous king, indeed. But who would dare compare? Stefan was already "dead", and no one would challenge Samael. Even if there were a few capable individuals, they already sided with him.
The seed of fear and grudge continued to grow over the years. During the first two years, people who didn't fear death had joined hands to stop his tyranny and even got some support from other small kingdoms. But the outcome was already set in stone.