WHY ARE THE TERRIBLE CULTISTS NECESSARY?

The Indigo Consumption spreads terrible wings.

[◙] Easy Mode – To appease the horrible thing from beyond with actions that are less terrible than destroying the entire planet. This leaves a great deal of wiggle room for some truly reprehensible rites.

{◙} Twist – It’s going to destroy the planet anyway when it feels like it. It doesn’t actually care what mortals are doing.

[◙] Medium Mode – There is a fragile ecosystem of souls in the afterlife. “Evil” souls are detrimental… but not to the degree that “good” souls positively impact the afterlife. (A crude but efficient way to explain it: think of good souls as vegetative producers, creating the energy that sustains whole heavens and entire hells. [Some “good” souls are still assholes, way too into punishment.] Wicked souls are bit like herbivores, playing a useful part but not so important. Then truly “evil” souls range from carnivores to terrible diseases in the ecosystem of beyond… It doesn’t work exactly that way, but, eh, close enough. )
So to keep the afterlife running smoothly, sacrifices must be made. A toddler is rarely wicked, an infant even less so…
Some don’t have the stomach for that so they instead hunt down wicked beings… before the cretins can become truly awful.

{◙} Twist – doesn’t really need a twist… other than to be true. The PCs might be horrified to realize that the baby eating cult they just murdered and the folks that hired them to bust up the local thieves guild are one in the same.

I’ll think up a Hard mode, later… maybe.