@givemersspls I agree that Hiraheishi did a better job on the emotional aspect, though I wonder how much of that is due to the artwork; New Saga's artwork feels kind of rough, almost sketch-like, so all but the most extreme emotional expressions feel... Muted, is the best word I can think of to describe it. Hiraheishi's feels more vibrant, in a way. I also have to wonder how much of it has to do with how Hiraheishi's protagonist shared his past life with his parents, whereas New Saga's MC has kept everything to himself, so the other characters come off as being less involved. At least, that's my take on it.
As for the demons' "Might is Right" system of rule, I'd imagine it's single combat to the death or surrender and it can only be a single ruler because if you had to gang up on the current ruler, you weren't strong enough to defeat them on your own merits, so the challenge would be seen as invalid and would probably result in the current ruler's supporters assassinating the challengers or just devolve into a full on civil war to determine the strongest. As you say, it doesn't really matter, but it'd be interesting if they explored it more fully.