D&D 5E A different origin for demons and other nasties...

[TheIdeaOfGood]

A world I am currently working on has as a premise that demons, devils etc. are not "true" Outsiders but beings formed from the evil of all sentient races. They have no existence as separate entities before coming into the world via summoning. Likewise, the "God"-equivalent in that world is basically a mindless force made from the desire of all sentient beings to be free of darkness and evil - of course, most worshippers do not know that...Now, the question is...should/would the evil outsiders work as they are or would you recommend some tweaking?
Also, what about things like the Obyrith/Qlippoth which are much stranger than demonkind?

 

[Li Shenron]

Now, the question is...should/would the evil outsiders work as they are or would you recommend some tweaking?

You don't really need to change anything, but of course you can if you want. You can for instance tie each Fiendish creature or type to a specific evil deed or thought, and allow the characters some non-combat way to diminish the creature's power.

For example you might decide that Vrocks are the embodiment of greed and each one is born when someone kills or harms someone for greed. Each vrock might even display a feature or carry an item by which you can identify exactly which crime generated it. Find a way to revert the crime and the vrock vanishes. Or manage to convince a whole town to be more generous and you can seriously diminish a vrock infestation that otherwise is too hard to beat by combat. The demon prince of vrocks however might be another matter, and as the embodiment of greed itself can't be destroyed until greed exists, but if you kill it in battle (temporarily of course) perhaps you quell the greed of the world for many years.

 

[Mercule]

I would strongly recommend reading some material for Werewolf: the Apocalypse and both Mage: the Ascension and Mage: the Awakening. They aren't dead on with what you're doing, but they very much explore ideas of the spirit world being strongly influenced by what happens in the "real" world. The entire premise of Mage: the Ascension is that human belief shapes reality.

To your actual questions, I first need to ask a question: Do the demons know of their origin or are they just as ignorant as humans? If they're ignorant, then I see absolutely no reason to make big changes -- maybe wait until you run across something specific that doesn't seem to fit, but they're going to manifest based on expectations and that manifestation will further solidify expectations. After a couple millennia, that form may not be what it started as, but it simply is. If the demons have a clue, that doesn't mean their form (abilities) will be any different, they may just resent certain... shortcomings and try to change public opinion.

I'm not really familiar with Qlippoth in D&D. A quick search turned up some Pathfinder info, so I'll run with that. Maybe the difference between the demons and the qlippoth is that qlippoth know what the demons don't -- their origin. Along with that, the qlippoth haven't been nailed down as much, so their abilities are a bit more subjective, as is their form. There's power in naming a thing and/or cataloging it. Qlippoth gain power by being less studied. A demon represents a certain, specific type of sin/evil; at most, a demon is going to represent a broad category of sin. Whether the naming of the evil or demon happened first is irrelevant. They simply are associated, now. A qlippoth, on the other hand, still gets to play boogie man and is the unknown evil. That gives them tremendous power because they get to draw on incoherent fear, which is vague, but runs deep. Should a qlippoth get too tied to an idea (or have that idea imprinted on it), it loses that power as it morphs into a demon lord.

The obyriths, on the other hand might be exactly what they appear to be -- evil that predates the known universe. Again, I wouldn't change stats unless you had a specific, concrete reason. They add a bit more interest in your model, though. What sort of conceptual evil could be so strong as to outlast the consciousness that spawned them?

Actually, now that I reread your post, I just realized that I missed that you were saying that these guys aren't "durable" beyond the summoning -- I think. I'd initially thought you meant that the Abyss, etc. were all created by mortal belief. I still think a lot of the above ideas could add some value, so I won't delete them. I'll add some additional notes, though.

I still say that you shouldn't change stats w/o a good reason. If you have no planes, anything that can shift has some obvious limitations. Beyond that, I'd just let it be.

Based on that, I'm going to flip demons and qlippoth.

I do like the idea, that qlippoth don't know they don't exist. Demons have this knowledge, and struggle against it. Obyriths actually do persist, but I'm not sure where they would -- maybe there's enough belief that the universe is starting to hollow out an Abyss.

In this model, there's a question of what the critters "remember". Qlippoth aren't mindless, so where do they think they come from? I'd go with them being created with memories of the Abyss, but it's all a bunch of fluff that doesn't matter. Or, qlippoth act as sort of "expert systems" that are extremely capable of doing the things they're built to do, but don't have actual sentience.

Demons are like qlippoth, but they have the knowledge of what they are. Basically, they now have a "hard drive" but "power off" when not in use. Knowing what they are, they're always looking for a way to return and/or stay for a while, so that they actually live. A qlippoth who gains true self-awareness might become a demon -- or that might be a terrifying moment as the weight of oblivion suddenly slams down on the beast.

Obyrith are the next step up. They get to "run in the background". What they do with their time and where they spend it is an open question. Maybe they can affect things or maybe they just get to stew and plot.

 

[MechaTarrasque]

I would consider adding something about them trying to become permanent (a certain amount of death, terror, etc. achieved), maybe some class levels (warlock and berserker barbarian are good choices) as they achieve some milestone on the way on the permanence.

Additionally you could look at the mystic and consider giving the fiends some psychic abilities since they are in effect psychic in origin. I wouldn't give them levels in mystic, but pick a discipline/talent and pretend they unlimited psi points to power (limit whatever the mystic can spend on the discipline/talent). If you are feeling masochistic, you could give them 1 psi point for 10 hit points of damage they do to a living creature (and/or kill, which makes fighting them in the middle of a crowd of commoners an iffier proposal), but that is more book keeping then I would do.

I am thinking it would work something like: the PC's fight a vrock (that only has an hour to be there). A round or 2 in, it books for the hills. The PC's find it 15 minutes later with blood on its talons, an extra hour of life, and 1 level of barbarian, so it is a little tougher. If it gets away again, when they find it, it has a whole day's worth of life and 2 levels of barbarian......