Kael was sitting on his throne, he looked bored, being King wasn't what he expected, he thought of people holding parades every day, but what he got was a lot of bureaucratic work, as well as matters relating to the nobles.
When he took over, he considered several nobles to be traitors to the nation, the penalty for which is death for up to the third generation of their family. A rather harsh penalty, but it was necessary to maintain order.
Some nobles really were traitors and sided with his brother while planning attacks to seize land in nearby countries.
But others were just nobles that Kael didn't like, or who had done something that could be solved by confiscating some property and withdrawing the title of nobility, but Kael feared that these nobles would revolt and somehow attack him.