Lore reasons for being faithless

Question

In D&D, religion is a real, tangible thing. Gods and deities are real, their blessings/curses on mortals are known, souls/the outer planes/the afterlife are all actual things. Denying them is like denying that air is real.

Yet there are people who do not worship and/or falsely worship gods (the Faithless and the False). In the Forgotten Realms, although the current god of dead, Kelevmor, seems to be a fairly mellow guy, his predecessors were not. There are probably other examples in other settings outside FR.

Former Gods of Death would decide whether they were the Faithless or the False. Either way, in the hands of Myrkul or Cyric, these souls eventually ended up being eternally tortured.

(Forgotten Realms Wiki)

Given how real gods are and the potential for an eternity of punishment, why do these people exist? Is there a good lore reason why common people choose to be False or Faithless, knowing that the risk is incredibly high?

Unless, the False/Faithless are actually a tiny minority of souls in the world and most people are active worshippers?

Edit: though I link to specific terms used in the Forgotten Realms (Faithless/False), I won't mind answers from other published settings, as long as it's an official published setting. Perhaps there was content or a published book that described a cleric or other scholar that did research into those non-believers, or maybe there was a scheme for devils/demons to influence the commom populace to stay as non-believers for personal gains, or some such in-universe lore explanation. However, minnmass's answer could also provide a clue. Perhaps the commoner in D&D settings are not as definiteively aware of gods as we think they are, despite the DMG stating so. If that is the case (and there is lore to prove it) then that could be an acceptable answer -- because the commomer doesn't know gods are actually real.

Answer 1

TL;DR

Faithless and False only existed in the forgotten-realms between 1996 and 2021.

Of Deities and Demigods

Back in 1980, TSR published the supplement "Deities and Demigods". It offered a toybox of divine beings, and titled many of them gods, demigods, and heroes. Looking from a religious eye, some of the mythos presented therein don't even have gods in the common meaning of the word. For example, the Arthurian Heroes are offered as a pantheon of divine beings, but none is classed as a god - and nobody would worship them but as a hero. On the other hand, the Cthulhu Mythos is offered as beings, and technically many of them are not even gods but Great Old Ones and Great Ones, and if you follow that pantheon by the letter of the mythos, most of those classed as "gods" don't provide power to their followers.

Of note is that the Arthurian mythos does not show up at all in the Deity list at the end of the book, where gods are given spheres of control, but they are the only stand out in that regard. Also note, that this was way before we properly got the Forgotten Realms. The book does not mention Faithless or Fallen - or afterlives as places to travel to in the first place.

Of Faith and Avatars

In 1996, "Faith and Avatars" was published, the deity sourcebook for the Forgotten Realms. It did bring us Faithless - and the reason they did exist in its intro. Read for yourself how the common folk of the Forgotten Realms gain "their" patron god:

Most folk have a handful of powers that they regularly venerate, only appeasing an unpleasant power when they are entering or engaged in a situation where that deity holds sway. Most people in the Realms also eventually settle on a sort of patron deity who they are most comfortable venerating and who they hold in the greatest reverence. A person’s patron deity is the power that eventually escorts that person’s spirit from the Fugue Plain, the place where spirits go right after people die, to its afterlife as a petitioner in the Outer Planes in the realm (or at least the plane) of its patron deity. (Those who firmly deny any faith or have only given lip service most of their lives and never truly believed are known as the Faithless after death. They are formed into a living wall around the City of Strife—Kelemvor, the new lord of the dead, may soon rename it—in the realm of the dead in Oinos in the Gray Waste and left there until they dissolve. The unearthly greenish mold that holds the wall together eventually destroys them. The False, those who intentionally betrayed a faith they believed in and to which they made a personal commitment, are relegated to eternal punishment in the City of Strife after their case is ruled upon by Kelemvor in the Crystal Spire (Kelemvor’s abode in the City of Strife).

p.2-3

So just delivering lip service without actually believing makes people just as Faithless as not having found a patron god yet. Yes, the gods are real, but which of the many gods do you want to worship? Many will follow the local customs, but if there's no fire in your worship and you just follow the motions to silence the community, then you are Faithless. If you found your personal pantheon, but not chose your patron among them, you are still Faithless. Most people will choose their god young, at least for their childhood, as they are brought up in their religious group, but they might go through a phase where they figure out who they really believe in, and to some degree, they might be among the Faithless in that time. And then there are those that deny gods exist, or are worshipable.

The False are those who had found their patron and then betrayed the tenets of the god, be it under pressure or from weakness.

Of Ed Greenwood Presents Elminster's Forgotten Realms

2012 brought us a re-presentation of the campaign setting, and it goes into a tiny bit more detail on when the gods of Faerûn considered you Faithless of False - it's a short list:

The average Faerûnian lives long enough to worship (or serve through one’s actions) one deity above all others—though in many cases, which deity a given person has served most might not be clear to a dying mortal or anyone else. If a mortal dies before finishing a mission or a task for a particular deity and it’s a matter he felt strongly about in life, he could be sent back by that deity, reborn as another mortal, to try to complete that task. Otherwise, he ends up in the afterlife serving the deity most appropriate to his moral and ethical outlook. Only those who repudiate the gods (or who as a result of their actions are renounced by their gods), despoil altars and frustrate the clerical aims of any deity, or never pray or engage in any form of deliberate worship will qualify as either Faithless or False.

p.133

The list is short: Disavow your god and you are Faithless until you find a new one to accept you. Be renounced by your god, and you are False. Despoil any altar or frustrate the clerical aims of any deity makes you False. And don't worship at all, and you are Faithless.

Why do they exist? Well, in a strange fashion, it's a tragic end for both heroes and villains: if you destroy the altars and temples of the enemies of your god, you might become branded as False from the opposing side, at least as Elminster puts it. And he ought to know, as he's Mystra's Chosen, and the sage of the Sword Coast.

Outliers from conjecture

Based on non-praying

Non-Outsider Creatures with souls who don't worship (like if they don't have a culture with deities) should be among the Faithless, but that might be a tiny group.

based on ownership of the soul

If you sell your soul to the Abyss or Nine Hells, you also might be considered False for having forsworn the gods, but your soul also wouldn't go to the Fugue Plane in the first place but right to your master to be turned into an inhabitant of their plane and one of their servants.

Of Sword Coast Adventure Guide

The False and Faithless as punished souls still existed in the early 5th edition, but there was not much of a definition for them but their punishment:

The truly false and faithless are mortared into the Wall of the Faithless, the great barrier that bounds the City of the Dead, where their souls slowly dissolve and begin to become part of the stuff of the Wall itself.

p.20

2021 SCAC Errata: False and Faithless Abolished.

In 2021, the Sword Coast Adventure Guide got Errata. These Errata erase the one mention of the False and Faithless, meaning that since that document, there is no more punishment for being a nonbeliever anymore.

The Afterlife (p. 20). In the second paragraph, the sentence beginning “The truly false and faithless ...” has been deleted.

Answer 2

Asmodeus is encouraging non-belief, to further his own ends.

According to Guide to Hell (1999), p.49-51, Asmodeus is permitted to claim the souls of non-believers, which he absorbs to recover the strength he lost in a primordial battle with the couatl progenitor Jazirian. To this end, he intentionally establishes cults which reject belief in the gods.

In worlds in which the power of gods is manifested through clerical spells, belief isn't hard to come by. However, there are always those who reject the divinity of the powers and the existence of an afterlife. [...] Unbelief is the tool of the Lord of Lies, regardless of alignment. These unfortunates are the true damned of the universe. While other petitioners strive to merge with their deities, the unbelievers are consumed by Asmodeus in the depths of Hell. [...]

So while the rest of the powers feed on belief, the Lord of Lies lives on unbelief. His true agenda is to promote lack of faith, not to fool mortals into embracing evil. The entire machinery of Hell, from the Blood War to the temptation of mortals to the politics of the infernal court, is nothing but a smokescreen.

Essentially, the souls of the dead travel to the plane of their deity, or to the plane of their alignment, essentially claimed by whichever deity most closely aligns to their beliefs. However, if someone rejects deities altogether, no deity can claim their soul, because all deities require belief. A god can't claim to represent the beliefs of a soul who doesn't believe in the existence of gods.

By this loophole, Asmodeus personally gets to claim their soul by default. So while the gods grant spells to clerics and perform miracles to prove their existence, Asmodeus has his agents raise cults and spread doubt. He does this mainly by three strategies:

• He encourages false prophets, so that their followers become disillusioned afterwards.
• He encourages philosophies that the gods are just very powerful creatures. One such philosophy is that of the Athar, a Planescape faction. Asmodeus didn't create the Athar, but he does quietly support them.
• He encourages conflicts between gods so that they appear petty in mortal eyes, and unworthy of worship.

Skeptics also exist in the D&D multiverse

As mentioned, there are groups like the Athar who believe that the gods exist, but don't believe they are divine. Essentially, they just think the gods are really high level NPCs. Clerics are just casting spells, and the outer planes are just worlds. Odin is just a really powerful wizard and Thor is just a guy who got really strong.

There are also low-magic worlds, or worlds where the gods' existence is less certain.

Answer 3

As far as I can tell...No. There is no lore reason given for why someone might be Faithless. Only what their fate would be.

I hit up the FR Wiki's entry on The Faithless, then pulled as many of the books referenced (which is most of them, I'm only missing the novel The Edge of Chaos--but what I can find about that one matches everything else I've seen) and spent some more time searching around for further references of The Faithless and checking those as well. The wall is introduced in Faiths and Avatars in 2nd Edition, and rehashed in the FR Campaign Setting for 3rd Edition. A few worthwhile snippets:

Original introduction: Worship in the Realms

Those who firmly deny any faith or have only given lip service most of their lives and never truly believed are knows as the Faithless after death. They are formed into a living wall around the City of Strife--Kelemvor, the new lord of the dead, may soon rename it--in the realm of the dead in Oinos in the Gray Waste and left there until they dissolve. The unearthly greenish mold that holds the wall together eventually destroys them.

--Faiths and Avatars, p.2-3

Under "Why choose a patron deity"

Of more concern to most adventurers, a character who dies without a patron deity cannot be raised from the dead by any mortal means short of a miracle or wish. When such a character dies, he is considered one of the Faithless, and his soul is used to form part of the wall around the realm of Kelemvor, god of the dead.

--FR Campaign Setting, p39

On "Patron Deities"

Everyone in Faerun knows that those who die without having a patron deity to send a servant to collect them from the Fugue Plane at their death spend eternity writhing in the Wall of the Faithless or disappear into the hells of the devils or the infernos of the demons.

--FR Campaign Setting, p232

On "The City of Judgement"

While most souls wander the Fugue Plane until their deity calls them, the Faithless and the False are compelled to enter the city and be judged by Kelemvor. The Faithless firmly denied any faith or only gave lip service to the gods for most of their lives without truly believing. The False intentionally betrayed a faith they believe in and to which they had made a personal commitment.

FR Campaign Setting, p259

In all of these references, the Wall of the Faithless is mentioned as a Thing That Exists. But I cannot find any record of an actual Faithless character that we would have the story of, or an explanation for why one may be Faithless.

Worth mentioning: it was originally mentioned in the Sword Coast Adventurer's Guide for 5E but has since been Errata'd out. I don't know exactly when this change was made, but the SCAG Errata says the following:

The Afterlife (p. 20). In the second paragraph, the sentence beginning “The truly false and faithless ...” has been deleted.

Honestly, the first quote may be the most telling--perhaps interpreted as: "It's a fantasy setting with gods, we want to strongly encourage players to pick a patron god, so here's the Bad Stuff that happens to your character if you do not."

Supposition - Fantasy Tropes

If this extension is unwanted, I can remove it...but without official lore, we can fall back on some old fantasy tropes (which the FR borrows frequently from) to provide some possible explanations. Some of these may sound familiar to you...

• "This tragedy that happened made me hate the gods, I curse them and will never worship them."
• "Sure, these things call themselves gods, but they're just powerful outsiders trying to extort people for more power."
• "The gods seek to keep humanity from realizing the divinity we, ourselves, are capable of. They are our enemies." (Taken from the Eberron setting, the "Blood of Vol" religion.)
• "I live in the middle of nowhere and nobody has ever told me about the actual gods that live in the Astral; I'm Animistic. Since I don't worship an actual god, I'm Faithless." (Argument could be made they are indirectly worshiping a nature deity, fwiw)
• "The local ruler has set himself up as a godking and demands our sole worship. Since he's not technically a god, that makes me Faithless."
• "I am a 'cultural worshiper,' I follow traditions and observe feasts because it's what my parents did--but I've never bothered giving serious thought to it and it's just a Thing That I Do."

Answer 4

The answers from Trish and guildsbounty are both fantastic, but there are a couple of things they don't address.

Because many people don't have the knowledge you are assuming they do.

Your question assumes that the average person has actual, first-hand or close to first-hand knowledge that the deities are real.

But I'm not certain that is true. Remember that the Forgotten Realms is roughly modeled around the late middle-ages. In that time period, the average person probably left their local village only a handful of times in their lives, and then probably didn't travel too far. The players handbook makes clear that real clerics that can do magic are rare. Most villages would have a mere priest "called to a simple life of temple service" unable to do magic, if they even have that.

There are probably a lot of people in the world that have never witnessed any clerical power first-hand and may not have even met someone who can testify to first-hand witnessing of clerical or divine power. In a world with limited travel, limited communications, no video cameras, and many people unable to read, it becomes very easy for there to be people that are hearing about the deities third-hand at best. And when you have only third-hand or worse accounts of something, it becomes very easy to not believe in that something, particularly when not believing saves you time, energy, and money.

In a world where the deities are occasionally flashy and overtly empower some clerics, non-belief would not be the norm. But if that world is mostly stuck in the middle ages, then its very easy for there to be people that never get that evidence in a reliable form and don't believe the unreliable retellings, of retellings that do get to them.

Because they were Deceived into a cult for something that's not actually a deity.

At least if you accept the earlier novels, there are things that are not deities that enjoy being worshipped either because of the control it gives them over that group or simply because they enjoy it.

I believe it was Crucible:The Trial of Cyric the Mad where there was a long conversation about that between Cyric and an elemental that had a cult worshipping him about how the elemental enjoyed the worship and actually did take care of its cult in return, at least during their lifetimes.

There are also frequent mentions of cults that worship dragons.

These people, even if they know of the deities, might think that their afterlives were secure because they were worshipping something. They may well not understand the distinction between the elemental/dragon/etc. that they are worshipping and the deities. This would be especially true if the powerful entity they are following is actively lying to them about that topic, which you would expect if they wanted to maintain the cult.

These people would then be faithless in the sense of having no patron deity when they died.

Answer 5

Every GM's world will have slightly different details, and those details may change from campaign to campaign. Some GMs put deities front-and-center, some keep them off to the side, and some eschew their direct involvement at all; similarly, some campaigns may expand to encompass an exploration of the planes while others stay closer to home.

For example: the last campaign I ran frequently involved the gods speaking directly with the PCs. The current campaign - with the same players - will have the gods fixed pretty firmly in the background.

Gods are real

We, the players, know that the gods are real. It's possible that the characters don't. It's even more possible - plausible, even - that random farmer #17 doesn't know that the gods are real; sure, he's heard about the major deities, but does he believe?

Such a person could easily be considered Faithless, for he may have "given no more than empty words of worship to the gods for much of their time and never truly believed". He could have prayed to Chauntea as he plowed and sowed, but if he did so purely by rote, with no belief behind it, might he not be called Faithless?

Souls, the planes, and the afterlife

A similar argument can be made for the rest of the soul's cycle. Maybe Farmer Bob heard of the Abyss and its infinite tortures, but he also heard that everybody from the next country over will stab you as soon as say "hello", then he met one who was a good egg, so maybe the whole "Abyss" thing is an exaggeration, too - or perhaps a tale told to children to keep them in line!

The False

In the real world, there are any number of people who do things against their own long-term self-interest in favor of some short-term benefit. In fact, people do it so frequently that we have a cliche about it: cutting off one's nose to spite one's face.

People go into eye-watering debt for a vacation. People quit good jobs for fleeting annoyances. People have affairs because their partner is out of town for the weekend.

Is it so strange that a devout worshiper of a deity might choose to do betray said deity for what seemed to be a good reason at the time?

The Faithless

Golarion, the default setting for Pathfinder (a D&D off-shoot) has a whole country of what would be Faithless: they acknowledge that the gods are powerful outsiders, but deny that they are worthy of worship. Compare the Gua'uld or Ori in the Stargate franchise: powerful beings, but not worthy of worship.

As mentioned, there may also be "background NPCs" who don't really have time for all that "religion" stuff - they'll pray to the relevant deity, but it's all pro-forma: just part of the patterns of life.

And, there are those who have been hurt by the gods. Maybe Farmer Bob's wife died while helping in the fields, and now Bob's once-fervent devotion to Chauntea has soured.

Unless the False/Faithless are a tiny minority

This depends on the GM's world and the story the group is telling. Some GMs might assume that only a tiny percentage of the population is False/Faithless. But, perhaps the story the GM wants to tell involves the party saving souls, rousing the Faithless to become the Faithful! Or, they may be being guided by a deity who seeks to take in those who have turned False to other deities - maybe a new deity of freedom, redemption, or even treachery is trying to rise to power; regardless, the GM would need to spread more than a few False throughout the world for the story to work.

Summary

In the real world, in the West, everybody knows that governments exist. They know that governments are real, their blessings/curses on the governed are known, courts/jails/prisons/parole are all actual things. Denying them is like denying that air is real. Yet, there are people who reject governments, who deny their authority, who break their promises to governmental authorities. Many who do so face a lifetime of punishment, yet such people continue to exist.

People do things that they know to be illegal all the time - when's the last time you saw cars actually driving the speed limit? And, people do illegal things without know that they're illegal (lots of stupid/silly laws are still on the books; it may be apocryphal, but I hear it's illegal to pass a cow without tipping your hat...). And, sometimes, people violate the terms of their parole.