Discouraging the soul-trade

Question

Creatures in D&D have a Soul. This concept is fairly un-explored, though.

In my current open-world game, one of the players has unleashed a number of Devils upon the world. (They are basically on cleanup duty, and do not pose an immediate threat).

So far, she's the only one who was willing to deal with them, and the other offers to trade a soul for power have been turned down because of roleplaying reasons. And that's a good thing, because I don't really know what to do if someone decides to trade their soul.

While from a roleplaying perspective it makes some sense to try and keep your soul, from a mechanical perspective the soul doesn't really do much for you. And this is a game with currently about 2 dozen players, ranging from roleplayers to powergamers. I don't really want to set a precedent that selling your soul is a cheap way into gaining power, as it would unbalance the powergamers and the roleplayers too much.

The only thing right now that would happen if a player would trade their soul, would be they'd be unable to be resurrected, but since the highest level player is currently only level 4, that doesn't seem to be a big loss.

Is there any lore in D&D 5e (or older editions) about non-roleplaying reasons for keeping your soul? What prevents characters from just trading it away for power at first opportunity?

Answer 1

The closest thing I can think of in 5e...

(Tomb of Annihilation spoilers ahead; not just little stuff, but the major unknown-at-first plot-point of the whole shebang.)

The dangerous artifact in Tomb of Annihilation hidden beneath the eponymous tomb is an Acererak-created one-off called The Soulmonger. The Soulmonger has two linked abilities.

(a) To vacuum up any souls that leave their body and intercept them before heading to their planar/religious/whatever-happens-to-souls-in-your-cosmology destination, making resurrection magic null and void (since the souls aren't available to stuff back into the/a body).

(b) To slowly draw souls that have previously been re-stuffed away from their body. This "death curse" manifests as any creature who's ever been the recipient of resurrection magic losing 1 hp off their max per day until they hit 0, at which point their soul is hoovered by the Soulmonger. This is the bit I think has some relevance for you.

We can see here that losing your soul does have mechanical relevance: you die without a soul. Period. Full stop. Even wishes are going to have a hard time countering this.

Though see "Nanny Pu'pu" in Tomb of Annihilation for a slight workaround.

So what should you do with this information? I'd suggest that immediate death is a silly outcome: it stinks for the player, and if the devil could do that as part of the bargain,why would anyone ever be alive "waiting" for their deal to come due? But the examples do suggest a mechanical, incremental, detrimental effect^* that the devil could be able to exert on the character.^** Whether this happens every in-game week, or every time the character does something the devil doesn't like, that's up to you. (And the player, if you want to share this bit of worldbuilding.)

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^{* it's the}

HP max loss, just to spell it out clearly

^{** - It's come to my attention that there are two different ways of thinking about what's going on here; they're both interesting (IMO) and don't seem to change much of the end-effect, but I'll spell them out just to be clear:}

^{1) The deal made with the devil gives the devil the power/ability to siphon away bits of it occasionally, until it's all gone and the character's dead;}

^{2) The deal immediately transfers the soul to the devil's possession but they use some magic to keep you going in some state of "life, but with conditions" (compare with magic jar or clone or the like).}

^{Either way, the devil's got their hooks in the character.}

Answer 2

The Classical Bargain

Traditionally (like, Goethe traditionally) the contract you sign with the devil gives you power while you live, and the devil gets your soul when you die. It's less of an immediate transaction where a radiant nebula drifts from your chest and into the sockets of an obsidian skull that bears a marked resemblance to you, screaming, now that you really look at it.

So, what do devils use souls for in D&D? Well, again traditionally, they're spent as currency in the Nine Hells, or as shock troops in the endless war. Either way, they're valued.

And why should a devil be content to sit and wait for something valuable when they can speed it on its way?

Mechanical Limits

So this is all going to work better if whatever people get from signing this contract is less of a one-time thing and more something they have to actively exercise. Someone wishes for wealth, they don't get a giant pile of gold, but they do find that their money pouch works like an everfull purse - put a coin in and sleep on it and more have shown up overnight. Someone wishes for strength, they don't get 24 Strength, but they do get to use a bonus action once per short rest to give themselves 24 Strength until the end of their next turn.

In addition to not introducing much of an immediate power imbalance between people who sell their souls and people who don't (and, you know, tweak the numbers so that at the point in the campaign you're at it doesn't really introduce an immediate power balance, 24 strength was just an example), this will let you put any combat-capable powers that characters get on the same action economy that everything else has to respect. You can even have the contract promise that, like the boring capabilities of the flesh, these hellish powers will improve with use.

Narrative And Also Mechanical Consequences

But every time those powers get used, mark it down. And whenever your campaign hits a meaningful stopping point, like returning to town after clearing a dungeon or whatever, try and roll under the number of marks for each marked character. If you do, clear the marks, and then... do something, based on how high the die rolled in order to clear it.

Sometimes powers should meaningfully improve just like the contract promised. But others... well, the devil has noticed, and become covetous, and will decide, boy, it sure would be nice if that contractor was dead and I had their soul. And they'll go after it through whatever mechanisms make sense.

Maybe that's a cultist with a twisted dagger in the dead of night. Maybe it's through odd and dangerous misfortunes in town. Maybe in the middle of a fight later on one of the creatures the contractor is fighting will suddenly become fiendish. Maybe their powers will fail when they'd rely on them most, or drastically change without warning as a completely different type of devil day-trades for their soul futures on the infernal stock market.

The point is, signing the contract gives the forces of the Nine Hells an arbitrary license to mess with that character forever. What are you going to do, call Hell's customer service and file a complaint?

Answer 3

There are already rules for selling your soul to a fiend

That would be the Fiend Pact of the warlock class. Someone wants to sell their soul to a devil? Take a level of warlock and choose the Fiend Pact. The roleplaying of making this deal and offering your soul is part of the backstory to how that level came to be—and it’s often a good idea to think about how you got the levels you have—but there’s nothing special mechanically going on here. It’s just a level of warlock, the same as someone else might have picked up a weapon and sparred some, and taken a level of fighter.

That’s it, no problems, no mess, no concern about roleplaying versus powergaming. Just use the rules that already exist. Waive the multiclass requirement, maybe, since the story explains how it happened rather than the sort of nebulous “well I guess with those stats you could have figured out how to do it” that the multiclass requirements normally offer—but then, I’d suggest making those “requirements” suggestions anyway.

At most, I would consider allowing the character to level-up on the spot when they took the deal, to represent the nature of the deal and make it a little special. But then their next level would be delayed to be the same as everyone else—after all, deals with devils often come with side-effects like that. So they would only be extra-powerful for a little while, immediately after taking the deal. Could still be pretty enticing in the right situation. Even a good and righteous character might be tempted if they’re desperate enough—sounds perfect for the Fiend Pact.

The devils can offer power, in the form of warlock spells. Up to the player/up to the character whether that’s worth it. Negotiating for and exploring devil-granted warlock spells does take some time, though, so there might be other things you aren’t doing—like taking a level in whatever other class you might have taken instead.

Answer 4

There is a great nugget from the spell speak with dead:

This spell doesn’t return the creature’s soul to its body, only its animating spirit. Thus, the corpse can’t learn new information, doesn’t comprehend anything that has happened since it died, and can’t speculate about future events.

Based on this, a creature without a soul is locked mentally; they cannot learn new things. Mechanically, This is going to be up to you as a DM as how to apply it. For instance this may mean they cannot gain experience depending on the DM. Your player might even count as undead, being animated but without a soul.

This will make for a very disturbing realization for your player; you gained power from the exchange but now you can't gain anymore levels or experience. This may very well be a delayed realization, or it could be introduced by meeting an NPC that traded their soul.

Imagine the end of the next encounter:

DM: "Players Y and Z, you gain 1000 XP. But Player X, you feel odd; the fight you just had feels distant and vague, you can barely recall it, almost as if it happened to someone else. You gain no XP."

They are not necessarily killed. There is plenty of evidence that removing the soul does not necessarily kill a person, both magic jar and astral projection explicitly remove the soul from the player without slaying them as long as the soul stays connected to the body. From the description of astral projection:

Your astral body resembles your mortal form in almost every way, replicating your game statistics and possessions. The principal difference is the addition of a silvery cord that extends from between your shoulder blades and trails behind you, fading to invisibility after 1 foot. This cord is your tether to your material body. As long as the tether remains intact, you can find your way home. If the cord is cut—something that can happen only when an effect specifically states that it does—your soul and body are separated, killing you instantly.

Another option is transformation. Lemures, manes, and wraiths in the Monster Manual are explicitly stated to be created/formed from mortal souls.

From p. 67, under "The Infernal Hierarchy":

Lemures. The lowest form of devil, lemures are the twisted and tormented souls of evil and corrupted mortals.

And from the entry on wraiths on MM p. 302:

When a mortal humanoid lives a debased life or enters into a fiendish pact, it consigns its soul to eternal damnation in the Lower Planes. However, sometimes the soul becomes so suffused with negative energy that it collapses in on itself and ceases to exist the instant before it can shuffle off to some horrible afterlife. When this occurs, the spirit becomes a soulless wraith-a malevolent void trapped on the plane where it died. Almost nothing of the wraith's former existence is preserved; in this new form, it exists only to annihilate other life.

Answer 5

Anytime I GM a table top and some one goes out of their way to sell their soul, I put a spin on it. I give them what they want however, they now they live to serve the one they sold their soul too. I treat it like Dracula siring lesser vampires. They hear a voice in their head telling them to perform certain actions that will meet the goals of the one who owns their soul. The Player character has no choice but to follow through with these actions. They are not even allowed to make saves against this. There is no way around it unless their "Soul Owner" dies permanently (Like erased from existence permanent). Its a great way to reign in your murder hobos. Also helps progress plots while creating a strife in the party they have to overcome. If players get mad remind them they have no one except their own greed to blame.

Answer 6

There are mechanical implications for not having a soul, you can't be brought back to life once you die

Traditionally, deals with devils for souls transfer the soul to the devil upon death of the dealee (as being alive without a soul is...difficult).

The Monster Manual provides this information on contracts with Devils (emphasis mine):

[...] a contract with even the lowliest devil is enforced by Asmodeus's will. Any mortal creature that breaks such a contract instantly forfeits its soul, which is spirited away to the Nine Hells.

To own a creature's soul is to have absolute control over that creature. [...] A soul is usually forfeited when a mortal dies naturally [...]. If a contract allows a devil to claim a mortal's soul before death, it can instantly return to the Nine Hells with the soul in it's possession. Only divine intervention can release a soul after a devil has claimed it.

Mordenkainen's Tome of Foes also has some relevant exposition on this:

Devil's constantly strive to recruit mortals into their ranks by offering them rewards in return for their service. While they live, these cultists carry out the wishes of their archdevil masters [...]. When a cultist dies, it's soul emerges in the Nine Hells and becomes another of the Blood War's immortal soldiers. Most evil souls become lemures, [...], but some mortals who willingly accept a contract offer from a powerful devil can arrive as a lesser devil.

and

[...] the Ruby Rod [...] grants [Asmodeus] and his underlings the right to enter into contracts with morals for their souls but unleashes an inescapable punishment upon any devil that breaches such a contract.

The Dungeon Master's Guide provides this information on souls:

Bringing someone back from the dead means retrieving the soul from [the plane of it's final rest] and returning it to it's body.

In addition, spells to return a creature to life require the soul to be able to return, which a demonic contract would prevent, as the "owner" of the soul has changed to an entity other than the soul itself.

Raise Dead requires the soul to be:

[...] at liberty to rejoin the body [...]

Resurrection states:

If the target's soul isn't free [...], the spell fails.

True Resurrection states:

If the creature's soul is free [...], the creature is restored to life [...]

A devil having a creature's soul would allow it to interrogate the soul for information. The spell Soul Cage provides some potential information on what this might mean:

[...] Query Soul. You ask the soul a question [...]. The soul [...] must answer you truthfully and to the best of it's ability. [...]

[...]

Eyes of the Dead. You can use an action to name a place the humanoid saw in life, which creates an invisible sensor somewhere in that place if it is on the plane of existence you're currently on. The sensor remains for as long as you concentrate, up to 10 minutes [...]. You receive visual and auditory information from the sensor as if you were in it's space using your senses.

In short, having your soul grants the Devil significant control over you. It can find out any information you know while you live, and view anywhere you are, or have been, and you will be prevented from magically being brought back to life unless a god intervenes. As a result, anyone you know, have information on, or any place you have been in the past may be in danger from devilish forces once you forfeit your soul.

For adventuring folk these are all pretty significant impediments!

Answer 7

I imagine that if you lose your soul, you also lose access to the gods. For paladins and clerics at least, that's the whole kit-and-caboodle.

But also to the extent that gods and religion are significant to the plot, it could be a real handicap if, say, not having a soul makes you basically invisible to the gods and their agents. I would also expect some especially pious NPCs to notice the lack of a soul, and any who have experience with evil might be likely to conclude that the PC is not a human/elf/dwarf/etc, but a monster in disguise.

Mechanically, holy spells like Turn Undead could very well also turn a PC who has no soul. Perhaps such a PC becomes vulnerable to Radiant damage, takes damage instead of healing from holy powers, and is unable to enter sacred places or tread upon hallowed ground. Perhaps a PC without a soul is, for all intents and purposes, undead.

And, who's to say what "natural" processes depend upon the soul? Perhaps the body of a mortal begins to decay once its soul is taken away, and the afflicted is now forced to resort to drastic and artificial means to keep themselves together. (Did you ever see Death Becomes Her?) I would definitely expect physical characteristics to suffer, especially Constitution. Perhaps the scores stay the same, but the modifiers swing toward the negative.

Finally, what about the impact on the PC's personality? Without the soul to tether their psyche, I imagine the freshly-undead will suffer from progressive Charisma penalties (and that's to say nothing of how visually off-putting it is to NPCs when you present as a leper, your skin has the pallor of a corpse, and your breath carries the aroma of a freshly-dug grave).

And then there's Grave Madness. As the mind recoils in horror from the walking meat sarcophagus it is trapped inside, the PC begins to see things: flashes of things that aren't there, glimpsed scenes of morbid depravity and inhuman torture. One stops recognizing the faces of their companions, and begins to see flesh and sinew stretched taught over bones, hollow automatons jerking awkwardly in a cruel parody of the living. Voices sound distant, food loses its flavor, and everything always so cold... There is no telling what someone seized by Grave Madness might do in their extremity.

I see penalties to skills like Diplomacy (distracted by visions, preoccupied by a feeling of alienness, hard to even understand what others are saying), Deception (loss of awareness of one's surroundings, inability to read facial expressions), Insight (monomaniacal fascination with the visceral).

On the other hand, I see the potential for bonuses to other skills, depending on how they are played, primarily History (morbid visions could be based in fact), and Intimidation (legit able to creep people out, and be outright terrifying for anyone who mistakes the absence of a soul as a sign of being a monster).

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I guess what I'm saying is: if your party is unable to imagine negative consequences to losing a soul, it's possible they've been watching too much Twilight and not reading enough H.P. Lovecraft. ;)

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I seem to recall that the Raven Queen is all about bringing death to the world. Perhaps she begins to take an active interest in a PC without a soul. That could be a bad thing.