Sundering and specific character questions. [Spoilers]

[Vyrerus]

Gordian of how the time lag/sync shenanigans works

So if we look at General Relativity and the Hafele-Keating experiment, we can see that when you move objects through space, time for them will speed up compared with any other objects closer to a center of gravity.

From the mess I cobbled together before, we know that the shards all have different Aetherial Coordinates while still occupying the same physical space. These Aetherial Coordinates make them further out of phase from the physical reality of the FFXIV universe, making them on that one plane, further from or closer to the gravity well of the Source. This means that their Aetherial Coordinates dictate how much faster or slower time passes on the Shards. Given that the Ascians essentially bring them in phase for Rejoinings, the closer a Shard gets to Rejoining status, the closer in phase it becomes to the Source's gravity well, causing their time scales to realign.

That's the best I've got on that. I would have gotten to it sooner, but I was preoccupied with my lunacy.

[Brightamethyst]

The lack of explanation for the time differences on the shards never bothered me since it's clearly just a plot device. They needed a way for it to be a 100 years ago, a month ago, and right now, all at the same time, and 'time sync shenanigans' is an easy way to explain it. The how and why is unimportant (probably.)