We're getting a "new complementary story" related to the Endwalker MSQ... (Spoilers)

[KageTokage]

As per the recent Famitsu interview involving Yoshi, Ishikawa, and Oda.

Given that they tend to typically refer to the side stories as...well, side stories on top of specifying that this story would be "smaller in scale but detailed", I'm feeling like they're going to adhere to the pattern of making 6.1-3 about tying up loose ends from the expansion's story with only the .4/5 patches leading into the next expansion proper.

With all the relentless Zenos avatar-related teasing Yoshi was doing even before the expansion's release, I'd be really surprised if the thing doesn't end up becoming a focal point in this story; moreso with Yoshi's not-so subtle suggestion that the voidsent behind it might be our shard from the 13th.