Just the Abyss and the Prime Material

[atemu1234]

I'm making my own cosmology designed to have nothing but demons (chaotic and evil fiends in general, not limited to the subtypes in FCI). There are no gods, no celestials, and I made it so Summon Monster I-IX only summon demons. I fully expect something unexpected to happen breaking this, so what can I expect to not expect from PCs?

[HunterOfJello]

Who exists out there to stop the demons from using a single Gate to invade the entire material plane and ruin it all?

Expect the PCs to do this.

[atemu1234]

Who exists out there to stop the demons from using a single Gate to invade the entire material plane and ruin it all?

Expect the PCs to do this.

That is basically what is occurring, at a slow rate. The PCs actually have to be holy warriors so gate is basically a nonissue.

[Arbane]

That is basically what is occurring, at a slow rate. The PCs actually have to be holy warriors so gate is basically a nonissue.

Where's the holiness coming from?

[Ravens_cry]

The power was inside them all along?:smalltongue:

[atemu1234]

The power comes from the Cause - works for clerics. They've devoted to a deity that may or may not exist. The Divine in this game either do not exist, do not interfere, or are incapable of interfering.

[Arbane]

Protection from Evil becomes THE go-to spell when fighting any sort of caster.

Are all Clerics evil? If there's no good gods in the cosmology....

[Eldan]

Where do souls go after death? Or at least non-evil souls?

[atemu1234]

Where do souls go after death? Or at least non-evil souls?

No one knows. Resurrection works, but the dead have no memory past dying.

Sorry if it seems like I'm changing things, but I swear this is how I intended it for flavor reasons.

[With a box]

Is astral plane still exsist? It is required for interplane movement in dnd

[atemu1234]

Is astral plane still exsist? It is required for interplane movement in dnd

There are random portals popping up in between the two so that isn't a problem, and portal spells required to work are refluffed.

[With a box]

I'm thinking about epic money throwing journey thought the PM to lock entire plane with Forbiddance (http://www.d20srd.org/srd/spells/forbiddance.htm)

[atemu1234]

I'm thinking about epic money throwing journey thought the PM to lock entire plane with Forbiddance (http://www.d20srd.org/srd/spells/forbiddance.htm)

The goal is actually to sever all planar ties to the Abyss. That may work.

[AuraTwilight]

How do spells like Astral Projection, Etherealness, Shadow Walk, etc. work, if at all? What about class features that emulate these effects? What about ghosts and other creatures that coexist on the Ethereal Plane, like Phase Spiders? Where do Elementals come from, if they exist?

[Phelix-Mu]

You could kind of do a Gehenna/Ossia-type of thing, a la Ao no Exorcist manga/anime, where, instead of being made out of pure cosmic evil/chaos, the Abyss is more of a demonic reflection of the Prime Material.

Why do this? Well, it might help answer some issues with why only two planes (they are reflections of one another), where do summoned elementals come from (they come from the Abyss, which, being infinitely large, has some of everything somewhere...assuming you are keeping the infinite bit), how about travel in normally Transitive Planes-stuff (well, the fifth-dimensional edges of the Prime might have shadowy/ethereally-type properties, but they aren't actually planes themselves), and allow for Abyssal conjugates of every kind of thing that might be encountered on the Prime (which are already implied to exist by the nature of the Abyss being infinite...somewhere in the Abyss, there is an Abyssal version of X, Y, and Z...like vampire demons!).

Just a suggestion, but it might help with the fluffing away of certain otherwise conflicts. Also, your conflict between Big Bad Evil Plane and the mortal world does remind me of any number of anime where that is the basic premise, among other works of fiction (which is to say it's a really cool, iconic idea to be developing).