What really is an aberration or a fiend, and does it actually make any difference?

[Yora]

For a campaign I'm working on, I decided that all planes are connected by the Ethereal Plane, and you can go from one plane to any other by going through the Deep Ethereal. Easy enough.
There is of course the home plane of the PCs, which is also home to other humanoids, beasts, and monstrosities, and an undetermined number of other planes that are the homes of various aberrations and fiends. All the cool layers of Gehenna, Pandemonium, and the Abyss that I like can be their own planes somewhere in the Deep Ethereal. But one consequence of such an arrangement is that there really isn't a fundamental difference between material planes and outer planes, and the only defining traits of demiplanes is that they have a limited size. But in that case, what's the difference between an aboleth and an arcanaloth, for example? How are they diferent from a lamia that is native to the plane of the PCs?
Is there even any point in distinguishing between aberration, fiend, and monstrosity?

[Temperjoke]

well, there are abilities and spells that can detect or affect fiends, but not aberrations or monstrosities (unless they also happen to be fiends of course).

[Mastikator]

In Eberron fiends are native to the prime material world, what makes fiends different from non-fiends is that they are spawned from Kyber. Aberrations are creations of the daelkyr who come from other planes, but most aberrations are natives.

You could differentiate them by what made them. Why do fiends even exist at all, why do aberrations even exist at all, why do humanoids and beasts exists? Answering that question could help tell the difference between a fiend and an aberration

[Millstone85]

Fiends are embodiments of the concept of evil, usually in a very simple way, i.e. they are supremely selfish, disdainful, hateful and cruel.

Aberrations are "wrong" on some metaphysical level, often brought by an "edge of reality" where everything unravels and misreforms.

[Chaos Jackal]

Is this a general "do we actually need all those monster types?" question, or is it specifically about, for example, calling all having all aberrations and monstrosities fiends?

If it's the former, well, probably not in your case since you don't really differentiate between origins, though you could still use other characteristics to separate and define them differently (a fiend, a monstrosity and an aberration don't just differ in their plane of origin, after all).

If it's the latter, then yeah, it makes a difference, at least for some classes and items. A paladin's smite, for example. It's not a very big range of effects, but they exist.

[Yora]

Reading the full description of demons again, one important trait they have, and which I guess could be extended to all fiends, is that they are ultimately spirits manifested in a physical form. They can spawn from the essence of their home plane, can be changed into different forms through demonic power, and regain their physical form if it is destroyed.

In contrast, aberrations are living physical creatures. They are born (or hatch), have parents, and need to eat food. That would make them similar to monstrosities, which also have these traits. The difference could be made that monstrosities are native to the home plane of the PCs, while aberrations are aliens from other planes.

(Fey have never really been justified as a category in any edition.)

[Unoriginal]

In contrast, aberrations are living physical creatures. They are born (or hatch), have parents, and need to eat food. That would make them similar to monstrosities, which also have these traits. The difference could be made that monstrosities are native to the home plane of the PCs, while aberrations are aliens from other planes.

A good way to summarize what aberrations are, IMO, is "wrong context creature".

Aboleths where once perfectly normal, but the world changed and they didn't. Illithids will be perfectly normal in the far future, but currently they are not. Beholders belong in dreams. Etc.



(Fey have never really been justified as a category in any edition.)

Fey are spirits of specific things, often natural occurrences or feelings, from the larger-than-life Feywild. For example, Boggles are created by a feeling of crushing loneliness, a Dryad is a tree's spirit, and the Eldadrins embody seasons.

[Izodonia]

Fiends are embodiments of the concept of evil, usually in a very simple way, i.e. they are supremely selfish, disdainful, hateful and cruel.

Aberrations are "wrong" on some metaphysical level, often brought by an "edge of reality" where everything unravels and misreforms.

In other words, fiends originate from - or cause - the evil that lies in the heart of man. They are very much like us, or at least, much like the very bad parts of us.

Aberrations are alien. They aren't like us. Unlike fiends, who cause evil for reasons we can understand (if not condone), aberrations cause evil for reasons we can never understand, because their minds don't work the same way ours do. Demons are immoral; aberrations are amoral. Both are equally dangerous.

[Millstone85]

A good way to summarize what aberrations are, IMO, is "wrong context creature".

Aboleths where once perfectly normal, but the world changed and they didn't. Illithids will be perfectly normal in the far future, but currently they are not. Beholders belong in dreams. Etc.Note that our "wrong context creature" and "edge of reality" approaches can be combined, if the aboleth past, the beholder phantasia, the grell homeworld, the illithid future, etc., are all so distant as to make the Outer Planes feel familiar in comparison. The Far Realm(s) indeed.


Fey are spirits of specific things, often natural occurrences or feelings, from the larger-than-life Feywild. For example, Boggles are created by a feeling of crushing loneliness, a Dryad is a tree's spirit, and the Eldadrins embody seasons.This.


In other words, fiends originate from - or cause - the evil that lies in the heart of man.I would say both, like a vicious circle.


Unlike fiends, who cause evil for reasons we can understand (if not condone), aberrations cause evil for reasons we can never understand, because their minds don't work the same way ours do.Which is where the story usually fails. Not only can you, by definition, not describe such motivations, but aberrations end up with very mundane ones instead, like survival, delusions of grandeur, or the reclaiming of territories.

[Devils_Advocate]

Yeah, aberrations aren't just alien to a particular plane, they're alien to the planes as a whole. And not just alien, but in some way antithetical. They don't belong in the overall cosmic order. Fiends are still basically classic horror, because they only represent the worst of human experience. Aberrations are cosmic horror, representing things outside of human experience that really shouldn't even be possible. Attempts understand them tend to result in madness, either because they're fundamentally incomprehensible to us or because understanding one of them is a form of insanity.

Cosmic horror, as I understand it, deals with fear of the unknown, and with the fear that unknown things just might be worse than we are even capable of imagining. Directly giving an audience impossible experiences isn't exactly feasible, and even if it were, the resultant shattering of their minds seems undesirable. So you can't show the scary thing, only characters' reactions and indirect manifestations. Aberrations are the latter. They may themselves be frightening, but the really scary thing is supposed to be the idea that they're only the tip of the iceberg, shadows of something unfathomably greater, a Cosmic Other to the fiends' Cosmic Evil.

[Draconi Redfir]

I've always figured there are two different types of Aberration.

"Natural creatures that just have non-standard features and organ placement", so this would be your Cloakers, your Chokers, Darkmantles, other small things like that. They're still natural being from the material plane, but they don't fit into any pre-existing category like "Mammal" or "reptile". And often their organs or other features are in unusual places, like a Choker might have it's heart down near where we would have our small intestine for example, so stabbing it in the sternum area wouldn't be as fatal for it.

And the second group would be "elder abominations from beyond the stars", these would be your illithids, your old-gods, your abboleths, maybe gibbering mouthers, etc. things that are clearly not natural to the material plane, and likely evolved or appeared spontaneously or have always been somewhere far away removed from what we know. This could be distant planets, the astral sea, the depths of space, etc.


things like fiends, celestials, and elementals all get their origins from planes that consist of primarily one element / alignment. Abberations could come from anywhere, or beyond.

[TaiLiu]

In Eberron fiends are native to the prime material world, what makes fiends different from non-fiends is that they are spawned from Kyber. Aberrations are creations of the daelkyr who come from other planes, but most aberrations are natives.

You could differentiate them by what made them. Why do fiends even exist at all, why do aberrations even exist at all, why do humanoids and beasts exists? Answering that question could help tell the difference between a fiend and an aberration
I really like this response. Construct a coherent metaphysics and slot the creature types in.


Which is where the story usually fails. Not only can you, by definition, not describe such motivations, but aberrations end up with very mundane ones instead, like survival, delusions of grandeur, or the reclaiming of territories.
I think this is a cogent argument. In fiction, writers have the ability to control situations and persons so that the whole alien minds thing works out. But it's probably much harder to do in a TTRPG, where you have to improvise and kinda get into the mind of abberations.

[Steven K]

I think this is a cogent argument. In fiction, writers have the ability to control situations and persons so that the whole alien minds thing works out. But it's probably much harder to do in a TTRPG, where you have to improvise and kinda get into the mind of abberations.

If they are present in 'our' world, they are in some sense a part of 'our' world. Aberrations are alien, but not fully. The really alien ones are the other things, out beyond the stars, in the Far Realm, beyond the boundary, however you want to say it. When they show up, the world becomes like the Far Realm, and that messes up the natural order of the normal world.

Aberrations are still bound somewhat by normal limitations - some need to eat or breathe, some probably sleep, they can all die if you try hard enough, so it makes sense that they would be at least partially understandable by normal mortal minds. We can recognise motivations in their actions, even if we can't understand or emphasise with those motivations enough to properly co-exist.

Beholders basically come into existence at random, as fully intelligent, in fact hyper-intelligent beings, and realise very quickly that the world is eminently hostile to their existence. They spend the rest of their lives in full-on survival mode. We can understand that. Aboleths want their empire back. Illithids want to eat and conquer and reproduce. None of that's totally foreign to our own experiences. We can't get into the mind of an Aberration, but we can work out their motivations and fake it, more or less.

But Cthulu or whatever other abomination from the Far Realm? Not a chance. There's no understanding, no common ground, just unmaking, fear, and death.

A little Cthulu (Cthulet?) is still just as much a mind-bending horror, without any discernable motivation or pattern to its existence. It's not a creature in the same sense an Aberration is. It's just a phenomenon.

[Millstone85]

A little Cthulu (Cthulet?) is still just as much a mind-bending horror, without any discernable motivation or pattern to its existence. It's not a creature in the same sense an Aberration is. It's just a phenomenon.According to this wiki (https://lovecraft.fandom.com/wiki/Cthulhi), it is a Cthulhi, also known as a Xothian or a Star-spawn of Cthulhu. However, these beings are described as waging wars and building cities. That includes the city of R'lyeh in which Cthulhu himself can be found asleep.

As I understand it, the Great Old Ones of the Cthulhu Mythos, including the dragon-octopus himself, are actually still pretty on the earthly (or other-planet-y) side of things. The real beyondness is with the Outer Gods, starting with Azathoth who is like a cross between the Flying Spaghetti Monster and Wonderland's Red King. See, Azathoth is asleep too, but while we do not want Cthulhu to wake up and start wrecking the place, we do not want Azathoth to wake up because he is dreaming the universe.

But "Outer Gods" wouldn't work in the Great Wheel cosmology, where there are already gods in the Outer Planes, so instead it is all "Great Old Ones". Also of note is that the strongest aberration in 5e so far is the star spawn emissary from Van Richten's Guide to Ravenloft. It starts as a CR 19 lesser emissary, then auto-resurrects on the spot as a CR 21 greater emissary that now spits gibbering mouthers. :smalleek:

[Catullus64]

At least as far as it impacts the campaign and the players' end of the experience, no, there's not a terribly meaningful difference.

The ideal role of monster categories, for me, should be to inform theme, not in-game lore or mechanics. That's the "Doylist" origin of these categories anyway: they represent groups of literary archetypes, flavors of fantasy, and aesthetics. The distinction between Fiends & Aberrations, for instance, doesn't exist because of planar lore or ethical philosophy, but because cosmic horror and classic religious horror are different literary categories. Any metaphysical or faux-taxonomic definition comes after the fact to this narrative motivation. It's in this particular context that Fey make sense as being their own group.

As a result I don't particularly bother to have these distinctions represented in the game world. Characters use the words devil, demon, aberration, and monstrosity interchangeably, often to refer to creatures that fit in none of those game categories. I find the alternative to frequently be a bit silly.

*Sees Gibbering Mouther*
Hark! What horrid devil comes upon us!?
Huh, I don't know if that's a devil. Looks more like a demon to me.
Maybe it's an aberration. Or a monstrosity?
*A thousand shrieking mouths in unison:* Shut up, nerds!

[Ganryu]

In simpliest terms, Aberrations are aliens, Fiends are devils.

Aberrations are generally twisted abominations that come from afar, and are never native to a plane. Many of them are from another dimension and go mad from arriving in prime material, though, of course exceptions. Mindflayers are aliens that really don't have a problem of going mad. They tend to deal with mind altering affects. They are 'aberrant' of nature, and not fully natural, nor constructed.

Fiends are devils, demons, and other creatures of the abyss, come up to harvest souls and have a stake in the prime material plane. They have no issue with living on the surface, but others tend to take issue with them trying. They tend to deal with soul altering affects.

And, not fully related, but the weirdest category is monstrosity. Nobody knows what the hell makes that one up. It's got phase spiders, mimics, and the tarrasque. THAT'S the 'misc, what do we do with it' category.

[Millstone85]

And, not fully related, but the weirdest category is monstrosity. Nobody knows what the hell makes that one up. It's got phase spiders, mimics, and the tarrasque. THAT'S the 'misc, what do we do with it' category.Yup, monstrosities "serve as a catch-all category for creatures that don't fit into any other type" (MM p7).

Or in meme terms, "Hmm yes that monster here is of the monster type".

However, my reaction to some monstrosities is that they clearly belong to another category. Phase spiders are beasts. Mimics are aberrations. All centaurs, not just playable ones, are fey. Etc.

[Catullus64]

Yup, monstrosities "serve as a catch-all category for creatures that don't fit into any other type" (MM p7).

Or in meme terms, "Hmm yes that monster here is of the monster type".

However, my reaction to some monstrosities is that they clearly belong to another category. Phase spiders are beasts. Mimics are aberrations. All centaurs, not just playable ones, are fey. Etc.

Beasts is also a weird category, since, with a very small handful of exceptions (Stirges come to mind), the only criterion for that category is that it be a "mundane" (that is, exists in the real world) animal, or at least a giant version thereof. But how the heck do people in the actual D&D worlds know what's "mundane" or not? I always wonder how Druids respond when people ask why they can turn into a Bear or a Giant Eagle, but not a Rust Monster or an Ankheg.

[Chronos]

Quoth Catullus64:

As a result I don't particularly bother to have these distinctions represented in the game world. Characters use the words devil, demon, aberration, and monstrosity interchangeably, often to refer to creatures that fit in none of those game categories. I find the alternative to frequently be a bit silly.
I was DMing a game once where the party was fighting some Shadows, and the fighter referred to them as "Demons from Hell". Which is of course wrong on multiple levels, and the fighter's player knew that, but the character wasn't particularly intelligent, and all that was relevant to him was "evil supernatural things that need killing".

[PhantomSoul]

Yup, monstrosities "serve as a catch-all category for creatures that don't fit into any other type" (MM p7).

Or in meme terms, "Hmm yes that monster here is of the monster type".

However, my reaction to some monstrosities is that they clearly belong to another category. Phase spiders are beasts. Mimics are aberrations. All centaurs, not just playable ones, are fey. Etc.

I tend to think of Monstrosities as "monster-ified" or "monstrous" (in the "deformed/created" sense); a plain Beast is a "natural" thing, without extraplanar or arcane or psionic or other influences and origins, while a Monstrosity is either unnatural by its creation (e.g. it's the result of Arcanist tomfoolery or experiments in the past [like Chimeric amalgamations]) or mutation (e.g. extraplanar influences "seeped" into the Creature [Phase Spiders]). In many cases, of course, that's fodder for coming up with lore as much -- or more -- than interpreting the Creature Type in light of lore! (I also like Centaurs as Fey, but hey, upgrading to multi-Type Creatures gives the lovely option of a "why not both?" I suppose! They are a bit chimeric [two things schmooshed together], so Monstrosity doesn't seem wholly sily to me, though.)

Of course, this is more worldbuilding than RAW, as is often the case in 5e xD

[subtledoctor]

There is of course the home plane of the PCs, which is also home to other humanoids, beasts, and monstrosities, and an undetermined number of other planes that are the homes of various aberrations and fiends. All the cool layers of Gehenna, Pandemonium, and the Abyss that I like can be their own planes somewhere in the Deep Ethereal. But one consequence of such an arrangement is that there really isn't a fundamental difference between material planes and outer planes, and the only defining traits of demiplanes is that they have a limited size.

Sounds like the old BECMI/Mystara cosmology. Keeps things loose, not being tied to a particular planar structure.

BUT this disrupts some definitions of what fiends are. In the old Great Wheel cosmology, remember that the outer planes are literally the afterlife; and natives of the outer planes are in fact the spirits of mortals formerly living on the Prime Material plane. (They do not have much "spirit" flavor, of course, and thinking about it too much makes for a weird overlap between fiends and undead. Though easy enough to decide that undead are simply spirits or otherwise dead mortals which have failed to make it to the afterlife.)

What later editions call aberrations are more like aliens from alternate realities or times, which have become rooted in the campaign universe like an invasive species in a non-native ecosystem. They are weird and don't fit into the naturl relationships of species in the Prime Material... but they are certainly not spirits taking on forms embodying philosophical principles in the afterlife. They are living organisms just like humans... just, unnatural in the human context.

[PhoenixPhyre]

One set of distinctions I like to make among aberrations, monstrosities, beasts, and fiends is the distinction between origin of type of creature and replication patter of an individual instance of that type. Basically creation vs reproduction.

Aberrations are not of natural origin, and they don't breed normally. They are all effectively individual creations. At most they have a progenitor/maker, but they'd never have a parent. They're alien to the normal ecosystems of the planet, even if they eat and drink and breathe.

Monstrosities are artificially (or otherwise unnatural) of origin, but breed normally. When a daddy manticore loves a mommy manticore...but without the intervention of something (not counting gods), there'd never have been the first manticore. They now participate normally in ecosystems at all levels.

Beasts are natural/natural. They are the foundation of the animal side of the ecosystem.

Fiends are "natural" in origin, but not of the material plane. They generally reproduce from souls.

--------

Of course my own setting has some twists on this--humans and orcs, for instance, would fit into the "monstrosity" category except that the humanoid category overrides it. They were artificially created out of hobgoblins + other "DNA" (although that doesn't really exist in the same way, but the analogous idea) by elves about 10k years ago. Along with the majority of the humanoid races, many of whom were created out of humans.

[loki_ragnarock]

Phase spiders are beasts.

I'd argue that Phase spiders (int 6), much like winter wolves (int 7) and worgs (int 7), are a bit too smart to be beasts...

... and I'd ignore giant owls and giant eagles, because that would fly in the face of that claim.

But then I'd claim that intelligence and flight would be the determiner...

... except the giant elk sort of skewers that whole angle.



Maybe the key differentiator is that beasts are more afraid of you than you are of them, and with monstrosities you are more afraid of them than they are of you?

[OvisCaedo]

I sometimes suspect that one of 5e's guiding principles for "beast" versus "monstrosity" was "do we want to allow polymorph to let you become one"

[PhoenixPhyre]

I sometimes suspect that one of 5e's guiding principles for "beast" versus "monstrosity" was "do we want to allow polymorph to let you become one"

I was about to say the same thing. Or wildshape. Or Conjure Animals.

Although then they went and printed the velociraptor and a few other beasts that break that model but are too obviously "natural" to fit into the monstrosity category.

<unpopular opinion>
One more reason why spells allowing monster-manual diving (limited only by the monsters/types available, not explicitly limited to specific stat blocks in the ability description) are bad for the game and why the Summon X line are so much better (from a game health perspective).
</unpopular opinion>

[Naanomi]

To be pedantic with old lore...

~Not all fiends are born of souls, some types arise naturally from the stuff of the Outer Planes (especially, but not exclusively, very old fiend types that predate mortal souls)

~Some fiends play at being cosmic horror types, Obyrinth (especially Pale Night) and Ancient Baatorians especially... Baernoloth also to a degree (who are comprehensible but have a very bizarre 'anti-utilitarian' clinical view of Evil)

~Some Aberrations have a semblance of a natural life cycle; reproducing and what not. Many of these are creations of other, more alien Aberrations. Cloakers (and a lot of the other beings listed above) were Aboleth creations, who have a real penchant for biomancy

~Aboleth were more comfortable in the ancient Prime, but were never natural to it in any meaningful sense... They were born when what may be the original Far Realm incursion being brushed up against Prime worlds after all

~Beholder lore has changed so much over editions it is hard to generalize anything about them in the extended view

~Although the specifics of Fey have changed a lot through editions, there has always been a bit of 'doesn't quite fit mortal schema, yet are still natural things' as part of their nature

[TaiLiu]

If they are present in 'our' world, they are in some sense a part of 'our' world. Aberrations are alien, but not fully.
I think we're in agreement here! :>