An area being heavily saturated with Fel energy doesn't make it the twisting Nether. That would be a major weakness to the Legion. Now if in the very depths of the raid, we actually walk through a portal and find KJ sitting on a throne in the Twisting Nether and kill him, then that's different.
Fighting Archimonde and KJ as the last bosses of this expansion would be stupid as hell? Yeah, maybe... from a gameplay perspective, but this the Lore Forums, where we talk about lore. And right now, 2 expansion final bosses are still alive and their forces are currently attacking us... KJ was already the final boss in Sunwell and Archimonde was already a boss in Hyjal raid. Archimonde was also defeated in RoC and he was defeated in the War of the Ancients. So yeah, I think from a lore pov, fighting Archimonde and KJ on Argus makes a hell of a lot of sense... but I also think the Legion being taken over by the Old Gods would also make a lot too. Nice to see you also agree with me on that :P
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I do believe it will. But I feel 90% sure that it will end with the Old Gods/Void Lords gaining greatly.
Personally, I always thought that the Legion would try to summon Sargeras to his avatar and instead an Old God would infest it, taking over the Legion. Even made a thread about it like 6 years ago. God a lot of shit feedback from people, but it's starting to look like I was right all along >
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That would be cool, but he needs to come late. He needs to go to Ulduar and unite with the rest and start churning out more Titanforged. Maybe he can gather some Mogu and Tol'vir too.