I personally draw the line at what is actually represented in the game in some form or fashion.
For example, all class and job abilities are fair game. Some less so than others (Dragonfire Dive, Holy, and Flare being the prime examples) but generally speaking, if a PC can do it in the game, it's fair to say a player can do it in their RP.
Cloning oneself would require a far more detailed explanation because the only representation of cloning in the game makes use of high (Allagan) technology, hence it is a different matter entirely.
Similarly, a player being able to fly at-will is simply not something that is done in-universe in any case, so I would also consider that a non-starter.
I personally use aether as an explanation for all the outrageous things that actually happen in the game in combat and such, rather than a justification for things that I make up on the spot. That being said, I do also like to imagine and speculate about what other things aether could be used for, but that's more of an imaginative and/or intellectual exercise than anything else.
For example, all class and job abilities are fair game. Some less so than others (Dragonfire Dive, Holy, and Flare being the prime examples) but generally speaking, if a PC can do it in the game, it's fair to say a player can do it in their RP.
Cloning oneself would require a far more detailed explanation because the only representation of cloning in the game makes use of high (Allagan) technology, hence it is a different matter entirely.
Similarly, a player being able to fly at-will is simply not something that is done in-universe in any case, so I would also consider that a non-starter.
I personally use aether as an explanation for all the outrageous things that actually happen in the game in combat and such, rather than a justification for things that I make up on the spot. That being said, I do also like to imagine and speculate about what other things aether could be used for, but that's more of an imaginative and/or intellectual exercise than anything else.