Quinella cannot be compared to previous descendants of the Original Four. What sets her apart is her exceptional understanding of and expanding on what they call the "Sacred Arts". And because she is a descendant of the one immoral Big Four, she likely was the first to understand that killing en masse would not only increase her authority level, but also that she could /use/ this to gain more and more control and authority over those "system commands".
Besides, to the denizens of the Underworld, the "System Commands" ARE divine/magic. They simply don't think in our terms and do not understand it well enough. That's why only select people are chosen to study it. That's why they call it the Sacret Arts. And Quinella taking lives to further her system authority is essentially dark magic - doing something highly immoral to meddle with the workings of reality and further her own power. That's essentially what dark magic is.
However, she knew that her extensive slaughtering of animals (maybe later people?) was highly uncommon and that no one had ever intentionally taken lives on this scale to do the things she did. She realized she was unprecedented, but she wanted to remain unmatched. And thus, even something as vile as murder was forbidden only to secure the reign of a murderer.
I'm sure the people who make these episodes had some time off for new years, just be patient. They deserve some time with their families, friends or just be alone in a room and watch anime like I'm sure we are all doing right now. But I still can't wait to see what happens.