A cursed environment

[Deeds]

Hi all! I'm here for a bit of brainstorming the next chapter of my campaign. Here's a bit of background. After thoroughly being defeated in the last chapter, the PCs are headed to a "no-man's land" in search of an artifact that is the embodiment of acid. The average party level is 12 and the optimization level ranges from 'I cleave' to 'full-caster with an I-win-button.' Optimization aside, the players have a good time and I enjoy being their DM.

The next area they will be adventuring to is cursed. The land itself is tainted with evil. An ancient kingdom and its surrounding territory was abandoned a thousand years ago after the atrocity that occurred there.

The point of the thread: how do I convey and create an environment that is truly inhospitable to non-evil creatures? This area should feel like another plane of existence: the water is vile, the vegetation is wilted or poisonous, and the wildlife are vicious predators. Thanks in advance playgrounders!

[Flickerdart]

A land of Evil should not be all vile grass and putrid water. The whole thing about Evil is that it embodies greed and temptation - the land itself corrupts the people. The fundamental way things work should be trying to tempt the PCs into acts of evil, ideally ratcheting up in intensity as they get deeper into the land.

So there might be a ton of greasy and inhospitable wasteland, and then a small oasis owned by a local. The local demands the PCs either leave or pay exorbitant prices for the rest and water. The decision to muscle out the NPC should feel tempting, because the NPC is visibly weak.

An alternative way of getting sustenance from these oases would be wild animals the PCs could eat - intelligent animals, possibly imprisoned in either a trap or a farm (since Evil creatures strive to dominate as much as they can). If you choose to have the "owner" present, he could even be willing to sell the creatures to the PCs for cheap, but then they must decide whether to eat the animal (and have food) or let it go. Alternatively, the creatures are already dead (in case you don't feel like letting them feel good by releasing them).

It's not about adding negative adjectives to everything, it's about crafting a space that is actively hostile to the PCs unless they are willing to stoop to its level and accept its laws.

[Ephemeral_Being]

The Ravenloft Dungeon Master's Guide has some suggestions for what are termed "Sinkholes of Evil." There's fluff material in there to help you describe them to your party, as well as mechanical changes that occur within the Sinkholes. It's REALLY good. I threw one at my party a few months back, and I remember being impressed by them. Essentially, extreme negative emotions on the material plane were manifested in Ravenloft. It has some suggestions for what those can be, but you could just use what's there as a guide to make up your own. They outline the process of both creating one as a DM, and for how your players could theoretically "cleanse" them.