*Spoilers* The Past and After the Endwalker MSQ End

[Jandor]

Honestly? We have no idea how changing the past of the Unsundered World will affect our world. We know that altering the pasts of different shards created different timelines, but the Unsundered world is incredibly dense in aether, to the point it's original inhabitants were outright immune to the effects of Dynamis, while people living in the shards will be transformed by it and be completely lost.

What we did in Elpis was a closed loop of events. Altering the events drastically, as in preventing the sundering of the world, could invariable destroy our timeline and that of the shards, and there's no way of knowing for sure because the Unsundered World's aetheric density is so much higher than ours.

Yeah, I've been operating under the theory that timelines require resources to make in this universe. You split Elpis and you end up with 2 timelines with half as much "stuff" to go around, potentially leaving our timeline too thin to support being split a further 14 ways later on.

Alex does warn about it IIRC. Pull at the threads too much and the whole tapestry will fall apart.

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On a different note, in-universe, I don't think anyone actually knows that the 8th calamity world survived.