You can get the bad ending by telling to Othra to tell to the others the existence of the Purification Lake
I tried that, but it doesn't work.
Combined Lust of Warriors and Acolytes must be at least 10 (You can see the numbers when you are on the main map while visiting the ruins)
Owo thank you for the answer. Gonna try this later. Even if I'm gonna feel bad about doing it.