They are probably scared not because he is manipulative or psychotic in a sense. But he is half 'monster' like those outside that town. They agreed to join him because they can have peace and living in that town. But since he is half human or maybe he still has human sense only, they are at edge around him.
Realistically speaking, the King being obessed with you is a lot to carry since he has more power over you. The best thing MC can do is to use the King's obsession for the better of the country and his goals of healthcare and poverty. Then if he gains the favor of others and everyone in the entire Kingdom for his good work, he can then overthrow the King from his position.









I bet atleast one of the authors who did a fan art side eye the ending cuz wtf is this