WotI across the Multiverse
by HåvardLet's say the Immortals did not agree to limit their quarrel to Mystara, but that the planes too were fair game. What would happen? The significance of influence/followers outside the Prime Material might be of less importance, but duking it out on other planes also means the gloves can come off! The Outer Planes might still likely have seen less action as most of the Outer Planes we know about are Home Planes.
What then of the Inner Planes? One answer could be that these planes are controlled completely by the Elemasters (or equivalent) and no interference is possible here. However, that's not very interesting is it? Granted the Elemasters will have their say, but it would be interesting if opposing Immortals could try to get wars started within the Elemental Planes because of WotI. Even cross-planar wars could be interesting. All in the interest of strengthening some Immortals and weakening others.
The Plane of Fire
One specific plane I have been giving alot of thought to is the Plane of Fire. Although officially controlled by the Elemaster of Fire who I guess answers to Ixion, it would make sense that someone like Rathanos would have followers on this plane. I doubt that the Elemaster would go and wipe out these followers, especially since there is a chance that Rathanos one day will succeed Ixion. The Elemaster's tactic might rather be to stay out of everyone's business and let them fight it out, as long as the situation doesn't completely destabilize. Also, there are probably other chaotic fire elemental creatures (Efreeti et) who secretly worship Entropic Immortals. Acting within the interests of the Brotherhood of Shadow, they will try to have such conflicts escalate as much as possible.
In a worst case scenario, the Elemaster does lose control over the situation, at least so much that the plane becomes vulerable to attacks from other elemental planes...
The Plane of Earth
Valerias is the only Immortal of the core Ring of Fire group to belong to the Sphere of Matter, and thus, theoretically she might have some influence on this plane. OTOH, she is of Hierarch Rank. She generally seems to be the most underestimated Immortal out there. Fighting against Valerias is fighting against love. She has set up a number of romances among the rulers in the known world. It is likely that the same applies to the planar rulers. The Fellowship of the Star has another Hierarch of Matter; Ka the Preserver. He is also not the typical earth elemental type of Immortal, but he might be able to counter some of Valerias' impulses. Earth Elementals are not those to be rashly driven away by emotions anyway. The fact that Kagyar stays out of the war also means that the conflict might not affect the Plane of Earth as much as it could.
The Plane of Air
Korotiku and Asterius are firmly on the side of the Fellowship of the Star, both Immortals of Thought. The Ring of Fire has noone. The one they would be most likely to be able to recruit is Halav, who might join to oppose Vanya. Odin would also be a good candidate for the Ring of Fire, but only if they are able to recruit Thor (unlikely?). The Northernes are not likely to split up over this.
The Plane of Water
Water is within the realm of Time. Vanya is on the side of the Fellowship of the Star, and the Ring of Fire has noone from the start. If the Ring of Fire is able to recruit the Traladaran Three (to oppose Vanya), Petra could have some influence here. However, neither Vanya nor Petra seem likely to have large followings on the Plane of Water. Perhaps Ilsundal could recruit Calitha out of elven solidarity?
The Plane of Shadows/Limbo
Odin and Nyx and the ones I gather have influence here. The more I think about this, the more interesting I think it would be if Odin (and the northerners) joined with the Fellowship of the Star. Not really sure if anyone from the Ring of Fire could gain much influence here though. The Brotherhood of Shadow might be able to stir up some trouble under that guise though?
The Plane of Light/Spirit World/Fey
Here's where things might get interesting again. I would assume that both Ilsundal and Eiryndul have some influence here, as would Ixion (as Tubak).Fey and Spirits are generally not too happy with Immortals, but might be interested in joining wars. Athruagin and group likely also have influence over some of the Spirits who dwell here. Which side would they take?