It just occurred to me that adventurers in D&D know pretty much for certain what will happen when they die (they go to the Outer Planar afterlife of their chosen deity). This knowledge among at least the more powerful people would seem to make them less afraid to die and more willing to charge into combat (as most adventurers are). Also, it would mean that evil deities need to have some better reward for their followers than unending torment (who would willingly sign up for that knowing for sure that was what was gonna happen?).

Any thoughts?

In my homebrew campaign, no one knows what happens to the souls of mortals after death. The reason mortals make deals with evil beings is to try to avoid the uncertain fate that awaits them after they die.

Many times, people choose Evil deities for a reward in life or unlife. 

There was a story in Baldur's Gate 3 about a devout person to the Lady of Loss.

In short, not everyone understands what rewards await them.

Thanks guys 😊. That makes a lot of sense.

@Thauraeln_the_Bold I like your approach.

Despite the available knowledge of afterlife in D&D, or maybe even because it, few would be in a rush to get there, likely because of lines of thought like Lyxen's laid out.  I think at least for those aligned with good deities, their faiths may aid their courage in walking a righteous path despite dangers, knowing their souls will be cared for in the beyond.  It may provide solace in some moments of loss too.  Of course dangers and adversity test faith, and after moment of doubt some may spend their lives in an effort to recover or prove their faith after what they or their religion saw as a fall from grace.  I feel like I'm almost writing about IRL faith, like Mordenkanian reads James' Varities of Religious Experience.

As for those leaguing with Evil gods and fiends, clearly no one's in a rush to become a maggot for Hades.  I'm sure there are some who actually think they have the capacity in their alliances to gain an upper hand, cheat death, or subvert the order of the Lower Planes to their own ends ... because in some lore that has happened (i.e. the Dead Three of the Forgotten Realms).  I don't think every evil collaborator has that motive though.  I think some are well aware of the most likely ends of their souls and do it anyway because it is the forces they identify with, their hatred against the more positive forces in the universe are that strong, the whole "some people just want to see the world burn" types.  To go maybe a bit too deep in psychology, there is thinking that the most pathologically toxic forms of narcissism are actually rooted in self-hatred, itself caused by an irreparable wound (somewhere in there is probably some cause why shattered mirrors are sometimes associated with demonic/diabolic energy, the world revealed in its ugliness, EGtW even has an artifact murder tool called "The Blade of Broken Mirrors."  Anyway, folks in that camp manifest a really twisted take on "wanting it bad" when it comes to Gehenna, etc.  On a literally shallower psychodynamic to address a different type of evil, there's the saying that evil is shortsighted.

Of course not all Evildoers or those striving the path of Good are necessarily theologically invested, depending on your game world.  And despite the presence of divine magic, what happens "beyond" may not have been revealed to most mortals, sort of like what I think Thauraein_the_Bold has in their world.

For one thing, not that many people in-universe actually know that much about the afterlife, aside from knowing that it actually exists.

And even for those who do, never underestimate the human(oid) capacity for self-delusion.  As one sourcebook put it "No tyrant looks upon a wretched lemure and thinks that this will be their afterlife."

Quote from Lyxen >>

Quote from 6thLyranGuard>>

For one thing, not that many people in-universe actually know that much about the afterlife, aside from knowing that it actually exists.

I am not sure why you would say this, there might be false rumours of course, but there is no reason for people to be less interested in the afterlife in a D&D Fantasy world than in the real one, and there are real and potentially trustworthy sources of information available, contrary to what is happening in the real world, if only the clerics that take care of their flock. A cleric of a lawful deity, known as such, would be unlikely to lie unless evil, and these are traits that are well known about deities, in the world.

 Because relatively few characters actually have the Religion skill or a serious bonus to it.  Your average commoner is probably attending service at the temple of Ilmater every week, but not necessarily paying terribly close attention to what they're told about the afterlife.

These are all good answers. Thanks.

On the Third Day I resurrect this thread with a revelation.  I've been working out in my campaign notes a sort of "economy of souls" that's really just in some preliminary thinking.   One challenge to the OPs assertion: Hellfire Weapon.  I'm assuming many felled by infernal iron were likely otherwise "destined" for other planes based on their faith.  So there are ways at least the Lower Planes, or at least Hell can drag souls into its forges to produce minor fiends.  It's an unsettling concept in this thought experiment.  I imagine the Upper Planes could accept souls on the 11th hour redemption track too.  So I'm guessing very few souls are truly reserved for particular deities or planes.  Whatever game the gods are playing amongst each other than involves humanoid souls is still a crapshoot.

D&D's version of good and evil does not allow for deathbed conversions to simply save you from the consequences of a lifetime of evil deeds.  You get judged by your actions, and that can have some serious consequences- some things are bad enough that not even a lifetime of good deeds is enough to grant salvation (see Planescape: Torment for an example).

Quote from 6thLyranGuard >>

D&D's version of good and evil does not allow for deathbed conversions to simply save you from the consequences of a lifetime of evil deeds.  You get judged by your actions, and that can have some serious consequences- some things are bad enough that not even a lifetime of good deeds is enough to grant salvation (see Planescape: Torment for an example).

You're right, though I didn't mean deathbed confessions, I presumed the wayward soul was able bodies and maybe finally on that right course in that 11th hour.  Just as humanoids don't fully fathom the afterlife, I don't know if they fully even fathom what the gods are getting at with the souls anyway.  So what moral calculus the gods ultimately use to assess a soul may be outside the ken of even the most devoted Cleric.  Again, with infernal iron, souls can be intercepted on pirated from where the conduct may have otherwise intended them.  I'm sure there are other diverting materials and magics too.  So if there's literally matter that bends the rules, it begs the questions whether mortals ever know the rules.

Interesting. I wasn’t aware of a Hellfire Weapon till now so I didn’t think of that. Thanks.