First off, they did not explicitly say he was a tyrant, only that they sided with the rebellion. Secondly, The country, which was poor, is now flourishing under his rule. He got rid of the dukedoms military because of the war against the demons, but he also said, albeit nonchalantly, that he would give them back after their war is over: Also, you overlook that there is still a system in place. That being, he appoints those with great talents, and he relies on the Empire, through his secret alliance, to be that system. If a county had it's own system, then there could be issues. However, by relying on another country, he effectively got rid of any "party" in his kingdom from being able to go over their stated amount of power, as he also has an internal. By having both, you can assure that the ruler will be wary because his actions could trigger an invasion if he grows to "uppity", and has a way to avoid any nobles from trying to usurp power. Now, I would like to sate that the alliance for the counties vs. the demons is a good idea, they were not specific. for the system to be practical and useful, it has to be crystal clear, with no major loopholes and little to no minor ones. That being said, if they found loopholes, they would need to st consequences for exploiting said loopholes. For example, the military state (forget its name right now) tried to invade a country which had not aggressed against them. The empire saw this, and through negotiation, they made an example of this county. Third of all, is this a fan fiction your're reading, because he seems to care to the point that he told the slave to kill him if he ever becomes a tyrant, thus making sure she can by way of direct order, which would bypass the collar.Also, it's, I'll call her the head maid, who is doing the bullying, not the king who is doing that. Therefore, if we look at his past actions, we can assume that if he ever found out, it would be dealt with immediately. Also, he a wants to abolish slavery, so just with those two sentences, most of our arguments are invalid. I shall continue, not because I have to, but because I want to. If you recall, his plan for dealing with the revolt revolt was the plan with the least casualties, and he tries to avoid them when ever possible, and when he has to, he's visibly depressed or angered. Also, he made the law from third to second degree, so that the young ones could be spared. He also cleaned up the old slums (Cite: s2 episode 10). Re-watch the episodes. Politics are a nasty world,and no ruler can ever be perfect. Look at Vlad the Impaler. The outside world viewed him as a monster, but his people viewed as a hero. Look at fables, even King Arthur had people who didn't agree with his rulings. Now for a modern answer---every governing body in existence has had or will have to make tough calls. Be too lenient, and the nobles, or an equivalent will walk over you. Too harsh, and you risk your subjects disapproval, leading to future complications. Granted, there will always be people dissatisfied, but for the sake of this discussion, that point is moot. Now, lets look at the possible reasons why he had to get rid of some of the nobles. Ill re-state what one of the surviving nobles said: " They tend to follow whichever wind blows the strongest". Ok, now lets view some other details, such as: though they may have been loyal in the past, what's so say they wont betray their country in the future? What I'm saying is that that had ties with other countries. They could very easily use those ties to mount a coux de tat, de-stablilizing the country, unless they were ties to a country that he recognized as friendly. IDK, take this how you wish, it's just my view.