Let's play a game: Save the Ancients!

[ZavosEsperian]

Granted, I've taken time away from the game in recent months, so if we've had more information that contradicts this then feel free to correct me, but how exactly do we know this? The last I heard, it was merely supposition. G'raha has never actually made the attempt to return to his time, so how do we - or they - know that's even the case that we couldn't return to our own?

The direct answer to this would be that there is insufficient evidence to back the claim that you cannot travel between Timesteam A to timestream B and then back to timestream A in terms of FFXIV, especially since the writers have used multiple different ideas as to how time travel works in FFXIV.

G'raha allows for us to assume alternate timelines that have no bearing on the host timeline do exist in FFXIV via his continued existence along with Tales from the Shadow: An Unpromised Tomorrow, which is a continuation of G'raha's original timeline after he leaves. Due to this timeline existing after G'raha in our timeline averts the 8th Umbral Calamity, the conditions required to satisfy his existence are not negated upon averting the 8th Umbral Calamity. Furthermore, how you view time travel in Elpis is open-ended as per the writer's wishes in a lore Q&A:

Q: I don’t really understand why the Warrior of Light messing around in Elpis didn’t create any alternate timelines. Can you explain what happened?

A: First of all, we’ve left that part up to interpretation.

-Letter from the Producer LIVE Part LXVIII (03/03/2022)

This quote above was spoken by Yoshi-P in Japanese and was live translated by Kate, all of which was on behalf of the writing team. Due to this, there is no definitive way to define the mechanisms used for time travel in this case without the use of headcanons. Anything else you have heard about how time travel works besides what the game says on the subject or what the writers themselves have said so far is strictly in the realms of headcanons as no one except for the writing team is an absolute authority on this subject.

The mainstream theory to how alternate timelines work is based around the Many-Worlds Interpretation, which given what that theory allows, would allow for all possibilities to exist across an infinite number of universes which make up a grand multiverse. While having two, independent, timestreams does lend itself towards this particular theory being the backbone of how G'raha Tia works, using two universes to justify every possibility being completely true in fiction is not a leap I am willing to make. I am only presenting this as to where the inspiration of G'raha Tia's time traveling antics likely come from. It is important to note the writing team did use a lot of real world analogues in developing certain in-game things, such as the Ea who directly cite how the end of universe will occur due to heat death or when entropy reaches its maximum or how Dynamis constitutes 68.3% of all energy in FFXIV's universe, which is similar to how Dark Energy (the expansional energy of the Universe) makes up around 68~69% of the total energy in the universe.

As far as what the WoL would experience, everything would seem like it is all one timestream. The only proof of external timelines regarding what the WoL experiences is G'raha Tia and his continued existence since he is from another timestream. We have the benefit as outside observers to know more than the actual character themselves because we are not part of the system.

Note I am not expecting anyone to read the links to all the science stuff I linked, I can barely get people to read official source material from the game itself as it is when I cite it.

I've yet to see any in this thread, nor even in any of the threads I've frequented in the entire time I've been here, including one popularly reviled as a haven for Ascian boot-lickers. It feels more like a fantasy that exists to conveniently undermine anyone with even the slightest inclination to question the Ancients' part in the story, honestly.

You probably won't see this because it is not necessary to do this in a universe where time travel as shown in FFXIV is allowed, which does include the likes of alternate timelines. Why someone would purposely bloody their own hands in a world of alternate timelines is beyond my comprehension.