Posted here instead of in Kerisgame since it's only tangentially related to there and it got a little too long for a side to the thread.
I'll note that my system knowledge is best described as "patchy" --- there are systems and sources from Exalted I've been able to access directly, especially homebrew, but certainly not all of it --- so while I've tried to keep this general and well researched enough to work, and explained the gaps in my knowledge I know about, if it looks like I've cited a bad source or don't know something obvious, that may well be the case.
So if you spot something badly wrong, by all means I outright invite you to correct me.
For the purpose of this post, I'm taking the Book of Ten Thousand Scorpions and the mechanics of the Unwoven Coadjustor rewrite and Kerisgame Hacks as canon. It likely won't come up all that much, but it's there in the background and may inform some unspoken assumptions.
No. This could potentially change specifically for Kerisgame, as
@EarthScorpion mentions
here, but I'm not too interested in doing so. Keris may, if she survives to elderhood and hangs around to the point where old age starts to threaten, finish off her life with some fucking huge Adamant ritual that externalises it, turns her hun soul into a Third Circle and basically sets up Krisity as an Elsewhere realm with links to Creation. Which will probably involve negotiating with Heaven beforehand to get permission and aid in setting it up, and so it would wind up as an allied realm with mutual defence pacts, evacuation agreements in case of another Great Contagion or similar and deva-summoning (fluffed as "calling on old pacts" a'la elves and men in LotR, so they're not just the summoner's slaves and may in fact require payment and respectful treatment). She would then, as a "first among equals" E10 Third Circle, proceed to be teriblu.
Two thoughts I just had.
Second, another good reason why humans can't enter an Infernal's soul-world even with the Infernal's permission is that the ability to have a Cult living inside your soul and constantly providing Essence refills would snap game balance over its knee.
Yeah- this is why, when I wrote Brazen Gates Unbarred,
@Aleph convinced me to put a fairly strict time limit on how long you could spend in the Domain if you weren't part of the Infernal's Mythos.
You know, this talk of entering the Infernal's soul world brings up a thought: If you wanted a basis for simple and relatively free interaction between the soul world and people other than the infernal and creatures from her mythos, without exposing the Po or Coadjuster or otherwise breaking things via invulnerable, perfectly provided for Cult, why not use the framework created by dream invasion and
Seven Nights Shintai as an inspiration? (Though I'd like to know whether there are also other issues that need to be dealt with beyond the listed ones I've seen discussed)
It gets by the "I keep my Companions and Cult in my soul" issue in that the participants are only sleeping, and thus still exist in the physical world and can be killed or robbed while sleeping and need to eat, drink, otherwise interact with reality, etc.
Likewise what I've seen of Dream Invasion (ES's Seven Nights Shintai, I don't actually recall if it's solitary or uses a framework provided by other charms) the charm provides a protection for at least one side of the thing (waking up with willpower loss instead of dying) on the side of the invaded. Invoking the rules of Fantasy Shaping to a degree gives a good a rationale to fluff that out into two way protection. The implementation that seems most workable to me is a meeting between two real beings where their mutual presence itself is the unreal thing. I imagine the protections would be something like:
"The thaumaturgy created by the charm allows a meeting of minds and souls within dreams where both sides can interact but neither is truly real to the other. While there can be permanent influence, for men weigh heavy in the minds of men, even those who have become worlds, neither the visitor nor any part of the Infernal may be permanently harmed within the dream. Being crippled or 'Dying' instead results in losing 1 wp as the mind recoils against the fantasy meeting, upon which either the visitor wakes or the deva* is restored to full health after five hours. Likewise either party can disengage from the shared dream at will, just as even the worst conversation can simply be shunned, even if there may be consequences later. In the case of the Infernal or her souls this results in effectively banning access, which may apply to anything from a broad group to a single individual"
*deva here being anything with a soul that's part of the Infernal's Mythos, There's probably a better broad term and the categories can certainly have room for refinement if desired. Harming beastial akuma but not anything more "important" as one consideration.
Or something along those lines. There's a pretty wide range of fluff and alternatives to that specific structure but this seems the best of the ones I can see.
As implied above mentioned It makes sense that the charm creates a thaumaturgy, as that allows a theoretically quite wide range of people in and, for reasons I'll get to later, the ritual requiring a payment to the Infernal of some sort also adds it's own benefits. Tangible, obvious, and otherwise.
In any event, this method of meeting in dreams allows you to go on and invoke a long tradition of visiting other worlds in your sleep when it comes to the perspective of the visitor. Make a deal with the devil in you sleep only to wake up beside your suddenly very physical ill-gotten gains? It's been done. (Though this one
does have the potential for Cult problems and the same sort of problems as VEE's canon problems. I really don't have the basis to know what would need to be done to make such a thing work.) Meeting someone within a dream and pulling them from the dream with you when you wake? Sounds a bit like Beckoning, which (if my source is correct)
is a six hour ritual, the difference being you're just 1) doing it in your sleep and 2) pulling someone with you instead of calling someone to you. Mortally offend someone? A traveler arcane realms, maddened with fear, seals and specially wards his room to prevent things from getting in to kill him via the cracks in reality. (One cannot help but imagine the Keruby as the Hounds of Tindalos. Well Keruby or a furious
Olajiyae if you want to be more serious and literal with "They get in through the cracks in the plaster on the walls".)
As to actual benefits for the Infernal: It's a secret meeting place for allies and the inherent protections on it mean that it's a place where for rivals and enemies who know of those protections can parley, (For that matter you could probably expand the "meeting of dreams" potential fluff into a charm for creating and allowing soul-embassies among other Infernals for the benefit of multi-player groups who are inclined to Kerisgame-style souls shenanegains.) And as for mortals? Well it's a Service the Infernal can Provide them. Even without the possibilities in the paragraph above this one, giving a payment (be it of prayer or goods) as part of a ritual for entering a world beyond their own and beyond the physical? Well, one could argue that that's something we're doing right now if we want judge its potential value and applications.
(And therein lies the joke: The Infernal, Green Sun Prince is can now be likened to Cyberspace, not in culture or trappings, but in structure, and you must pay a
literal hell being to access it.)