Well played, Baal. Very well played. I can't wait for your fall from grace, but I am sure it will be epic.
I loved Sullivan's answer about Iruma.
There is a thing to be said about "heroes" and that is heroes do not become demon king/lord
while alive.
But yeah, cold logic at this point indicates a rebellion will be coming. The demons may respect the princess's authority atm, but the person herself is absolutely meh. There are too many conflicts of interests amongst the various demon factions, but so far "peace" has been kept with the checks and balance of the 3 greats.
What Baal just did is essentially "down and out with the old rules of check and balance" and replacing it with "I'll be rewriting the rules with the princess's authority." Dumb princess needs to step back and recognize she should not be interfering with demon world politics - only as an external arbitrator and leave them to resolve their issues with their own means. Even if the 3 greats are colluding, there is no rule or guidance written that she can overturn/veto them - only that she has to enforce existing rules and punish them if they harm her faction (heaven's?) interests.
As for "Leniency and Punishment"? There is no crime here, the only crime here was Baal defied Delkira's contract before becoming demon king. At least, I don't believe Baal can become demon king with only Shura's support. And given what he just did to spit on the 3 greats, there's gonna be a lot of bad blood as he's also competing against their grandsons (let's not forget the ongoing demon king competition amongst their grand children/children).