@The 42nd Gecko
The sword can't really retroactively revert causality like that. If it did, then Artoria would never have been in that fight, Eos would never have had to use that attack, and therefore Artoria would still exist. But then, because Artoria exists, it would also not exist. Which then logically means that they do exist, etc.
Effectively time and space would be caught in a broken code loop.
Also, I imagine it would be a pain making all the tiny retroactive adjustments necessary to indicate what would have happened if Artoria had never existed.
The sword can't really retroactively revert causality like that. If it did, then Artoria would never have been in that fight, Eos would never have had to use that attack, and therefore Artoria would still exist. But then, because Artoria exists, it would also not exist. Which then logically means that they do exist, etc.
Effectively time and space would be caught in a broken code loop.
Also, I imagine it would be a pain making all the tiny retroactive adjustments necessary to indicate what would have happened if Artoria had never existed.