James Jacobs
Adventurer
Neat! The thought of aboleths evolving into mind flayers is an interesting idea. I've always thought that the two races were too similar in goals and abilities that there had to be some sort of connection.
If you go with this concept, I'd consider making the aboleth the ones who don't really know about this while the mind flayers do. The fact that mind flayers confound the aboleth so much (they can't remember where they came from) gets even better if you have a big moment in your campaign when the PCs prove to some savant aboleth that they'll eventually turn into mind flayers.
Also... the aboleth have been around for a loooooong time. I'd even say millions of years (although of course, not all campaings have histories that go back that far so your mileage may vary). And in those millions of years, they haven't changed much. They'd know, cause they'd remember. So, if I were running with this concept, I'd set it up so there was some monumental change or magical event that caused aboleth eggs to hatch mind flayers. Maybe the mind flayers are themselves responsible, having gone back in time to illithid-up some eggs? Since illithids from the future can go back into the past, there's no reason they can't go back before the point of their genesis (in the future from the present), so you can set up this event as a campaign climax and still have mind flayers fighting the PCs before they were technically created.
Crazy stuff!
If you go with this concept, I'd consider making the aboleth the ones who don't really know about this while the mind flayers do. The fact that mind flayers confound the aboleth so much (they can't remember where they came from) gets even better if you have a big moment in your campaign when the PCs prove to some savant aboleth that they'll eventually turn into mind flayers.
Also... the aboleth have been around for a loooooong time. I'd even say millions of years (although of course, not all campaings have histories that go back that far so your mileage may vary). And in those millions of years, they haven't changed much. They'd know, cause they'd remember. So, if I were running with this concept, I'd set it up so there was some monumental change or magical event that caused aboleth eggs to hatch mind flayers. Maybe the mind flayers are themselves responsible, having gone back in time to illithid-up some eggs? Since illithids from the future can go back into the past, there's no reason they can't go back before the point of their genesis (in the future from the present), so you can set up this event as a campaign climax and still have mind flayers fighting the PCs before they were technically created.
Crazy stuff!