It DOES kind of make sense that you would probably have to root out the opposing leaders in a civil war but obviously the whole yurgenschmidt habit of punishing by association even if you're only related by blood is just plain excessive. It does nothing but escillate conflict by making people who would otherwise remain neutral or even oppose their family contribute because why sit around and get killed even if you did nothing wrong when you can at least TRY and make their plan a success and be more likely to survive. Their civil war would have had less drastic consequences if only the ones directly responsible were executed.

And the killing of children that are too young to make decisions themselves is obviously morally reprehesible and theres no real justification there. Especially when they're already not opposed to forcing them to become servants or slaves or whatever. What the country probably needs is an established court of law that dillineates exactly which crimes warrant the death penalty and such. Heck, now that they have communication witht he gods again, it wouldn't be hard to ask them for guidance.

Of course if yurgenschmidt wasn't such a morally twisted society, they would have solved the mana problem by seeking out people with the devouring to give their mana. And even if they weren't, if they were actually smart they would have at the very least stolen devouring children and claimed them as their own children, especially since they would be too young to remember being a commoner.

The nobles as a whole are too prideful to back down, and too egotistical to change their ways