What kills a demon?

[rweird]

Outside of the abyss that is, in fiendish codex, it specifies that they return to the abyss to reform (though might be demoted), unless something is done to stop it. It gives the example of Dimensional Anchor as preventing the demon's rebirth. Does this mean anything that blocks planar travel at the time of death would? Would an anti-magic field/dead magic zone?

This is all in addition to things that trap souls normally such as Soul Bind, or destroy them, such as a Devourer.

Ideally, this is specified in some book which I haven't found, though if not, what would you rule would stop a demon's soul from returning to the abyss?

EDIT: I guess I should clarify some things, I am the DM, and as I've introduced a number of demons into a campaign of mine (on the prime), I want to know what would trap, as mentioned in Fiendish Codex I: Hordes of the Abyss, saying that demons reform if slain outside of the Abyss "unless trapped by magical means such as a Dimensional Anchor spell." The PCs are unlikely to go out of their way actually trapping the souls via Soul Bind, although they may accidentally trap a demon depending on what counts.

[AuraTwilight]

Well, you could always kill them ON the Abyss, which would kill them as a normal creature.

And generally, no, anything that blocks planar travel or the like doesn't stop souls from moving through the planes. Antimagic Fields and Dimensional Anchors don't cause ghost sites, afterall.

[rweird]

Well, you could always kill them ON the Abyss, which would kill them as a normal creature.

And generally, no, anything that blocks planar travel or the like doesn't stop souls from moving through the planes. Antimagic Fields and Dimensional Anchors don't cause ghost sites, afterall.

I'm aware that is not normally the case, however Fiendish Codex: Hordes of the Abyss mentions how it returns to the Abyss "unless trapped by magical means such as a Dimensional Anchor spell." I'm pretty much wondering, what would count as trapping it any preventing the demon's reformation, and if any other book specifies this in more exact terms (or I missed it in the Fiendish Codex).

[Samalpetey]

A thinaum weapon would probably work, but might want to double check with a DM before trying it

[Kazudo]

I question whether a Thinaum weapon would work.



Unlike most other living creatures, an outsider does not have a dual nature—its soul and body form one unit. When an outsider is slain, no soul is set loose.


Which says to me that without a soul being set loose, you can't absorb the soul if you catch my drift. Dimensional anchor actually makes sense. Antimagic field however doesn't, since what they're doing is not an explicitly magical effect.

[rweird]

Does that mean that Soul Bind likewise wouldn't work, although a demon being killed in an area under a Forbiddance/Weirdstone would prevent the demon from reforming?

[Kazudo]

I think that puts it squarely in DM Fiat territory (Though I'm not well read on the Fiendish Codices).

RAW is ambiguous about that fact. However, since Soul Bind says the following:



You draw the soul from a newly dead body


And the above quote specifies that the soul and body are not separate, I can see one of two outcomes. Either:

A. The spell doesn't work, since the body and soul of an outsider are not separate entities
or
B. The spell works and draws the outsider, body and soul (since they are a single unit), into the gem.

But that's DM Fiat territory unless someone else can clarify with a bit more RAW.

[captain fubar]

the summoning sub school will it give a body made from the matter of the local plane that is controlled from its current location so when you kill it it really wont care much.

the calling sub school on the other hand forces it to come fully into the plane where the caster is so when you off the fiend it will not only die but leave a corpse that is often a good target for undead creation, with a few exceptions like the exploding balor.

attacking it on its home plane will also destroy the individual though the fluff is a little inconsistent on whether it is then absorbed into the plane or reincarnated typically either into a much weaker form or only after a long delay