Recently I put a horror adventure in the DMG based on the story of "The Shadow over Innsmouth" and in a few days I plan to upload another one related to the "Texas Chainsaw Massacre" film and although I enjoy designing the modules, I realize that there are different difficulties to implement a terrifying environment in 5th edition D&D games, due to the tediousness of the combat and the multiple mechanical possibilities of the characters from level 3 onwards to solve the many problems they face, depending on the type of class, some characters are like Swiss army knives with legs.
WotC is well aware of this situation, since it tries to make changes on the rules with the Ravenloft module brining really uncomfortable topics to the game table, otherwise, the game does not work effectively to generate a horrific atmosphere. And this happens even in its first edition, but due to the limited tools the characters had in the first edition, it was easy that the simple exploration of a tomb ended up becoming a horrific massacre.
Attracting that pressure to new editions of D&D tends to get a little complicated, so I love to dig into old modules, twist them and give them a macabre approach. So in a future module I want to give a macabre twist to the classic "The keep on the borderlands" module as it was done in the Dungeon Craft channel. With the difference that although I want to give it a touch of dark fantasy and realism, I am more interested in focusing on the tropes of a more cinematic horror. So I can leave out the corrupt nobles, but I'll stick to the sinister traps and old edition monsters in a mutant or demonic fresh version.
I will respect the contributions made by Professor Dugeon Master, so I will look for plot twists to the classic module that are fed from other sources of pop culture.
Personally I like very much the module of "Out of the Abyss", because of the idea of leaving the demon lords free in Faerun, but without having a full use of all their abilities, which makes possible a lot of conflicts in several cities and towns. So the main villain of my version of the caves of chaos will be one of the demon lords.
In order not to make use of the classic fortress at the edge of the civilized realm, I prefer to make use of the world of Faerun, so instead of the impenetrable fortress, I prefer to make use of the village of Phandalin which is close to the city of Neverwinter and has a lot of games available from the Wizards and the community at the DMG. Phandalin works perfectly, as it has different conflicts going on around it and has npc's that already have a certain relationship with the adventure group. Besides the fact that we have a group of mountains close to the village, where the new caves of chaos will be located and since the village it's famous, isn't complicated to have several replacement adventurers or reliable torch bearers without faces.
THE VILLAIN:
It is vital to define the villain, because its nature can give us clues about the type of chaos that ended up invading the caves and therefore, the region around them. However, it is difficult because of the striking nature of each demon lord.
I want to avoid the violent Baphomet, because I feel that it would make the module too difficult, since its influence could easily end up perverting multiple npc's, to the point of transforming them into minotaurs...however, it sounds very cool that the village tavern owner can change his form at a time when the adventurers are drinking.
The good Fraz-Urb'Luu I already used him once and although I like how villainous he is, since he gets stronger as more conspiracies and lies are waged around him, the truth is that it changes too much the essence of the original module, which focuses on exploration and strategy, leaving negotiation in a secondary level. Of course, negotiation is very valuable to make one group of creatures fight against another, but it is not a complex plot. I think the gargoyle will fall asleep.
The Demogorgon, Well.. I'm not really inspired by it. Juiblex, being the god of the gelatinous cubes, invites you to get creative, because it invites you to imagine different acidic and gelatinous versions of the typical creatures, the same for their appearance and behavior. It would be easy to deduce that I arrive at the region infecting and making everything sick in its path.
Orcus and the Lord of the Gnolls are a bit simple for me, but both could work since they have servile and extremely violent hosts, but the truth is that I am more interested in the possibilities of the perverse lady Zuggtmoy, who by transporting her dark influence through mushrooms, could easily be present in the whole region, generating zombie mushroom creatures of the "Last of us" type, which could unleash a chaos that would invite the players to take action.
I still have to think about it, but at the moment I find myself between the lord of the beasts and the lady of the mushrooms, a group of organisms that can easily reach the lungs of the players and even though the queen was a cause for mockery in her first appearance, it would be good to give her some recognition.
This is just the beginning...