In The Clone Wars, the Son broke the laws of time and showed Anakin Skywalker his future. Thanks to Obi-Wan and Ahsoka, Anakin never managed to leave Mortis but one can't help but wonder what would have happened if they failed. In Legends, Abeloth did ineed sow terror through the universe and was much more of a threat than Darth Sidious ever was - the Son was on a somewhat equal power level...

I made this interactive audiobook of sorts that explores this narrative:

https://youtu.be/yirZAaufS5c

And what do you guys think would have happened? Would love to hear other perspectives on this!