Its interesting.
The most recent chapter at the moment Im typing this is 372, where Iruma just finished establishing the Many-Ear's own continent for his rank 6 exam.
The grandson of the leviathan, in light of this, seems a lot more intimidating now, if his exam was of a similar caliber. Being rank 5 means you're at the peak of where the demon education system can bring you, but to have already surpassed that at this point in the story?
At the same time, giving his aims more attention, he also frightens me a bit, because he aims to provide freedom through rule of law. Freedom through restriction. I mean the other grandkid is also terrible, but leviathan basically just wants fascism.