I must horribly backwards and out of touch. TERFs???
Almost every conventional Deity in Eberron might be an incarnation of one of the Sovereign Host or the Dark Six. Vulkoor might be the Mockery of the Dark Six.
I'm curious does Vulkoor now count as a member of the Dark Seldarine now? Is his worship not exclusive to eberron anymore.
Note that they didn't talk about just the Dark Seldarine, they talked about the drow pantheon. That means all the drow gods, from any world. Looking at the 3 deities mentioned by Crawford, Vulkoor is included because he is active in Eberron; Eilistraee is included because she is active on Toril (she doesn't have influence outside of Toril); Ghaunadaur is a drow deity on Toril, but he's more than that outside of that world (since he's basically an aspect of Tharizdun).
The Dark Seldarine is a synonym of drow pantheon only on Toril, that doesn't mean that other drow deities can't exist outside the Dark Seldarine in other worlds.
although the membership varies from world to world just as the regular Seldarine does.
I've only seen the name Dark Seldarine mentioned in FR material, but that's what I meant in any case. The fact that Valkoor is included in the drow pantheon is because he's part of the drow pantheon of Eberron (do you call that the Dark Seldarine of Eberron?), and is therefore part of the multiversal drow pantheon. It doesn't imply that his identity has been changed, or something along those lines.
The Seldarine is a multiversal phenomenon, the Dark Seldarine derives it's name from the Seldarine, so it's reasonable to expect that the Dark Seldarine name while universal, would be common in any crystal sphere that both Pantheons are present, driven by the same forces that lead to those in FR calling the Drow Pantheon the Dark Seldarine.
One thing I want to know is will there be a Shadow Seldarine between these two Pantheons?
I must horribly backwards and out of touch. TERFs???