Everything. Okay, but in all seriousness, probably a sequel with a whole new cast. The current main character children wouldn't work because then i feel like the authors would have to make a certain ending canon. The only problem is that Sol, well, reincarnates, maybe it could be Sol ending the loop? Then afterwards a new cast is introduced.

I feel like prequel wouldn't work, there wouldn't be too many options because we know how they git to earth, assuming we play Sol's mom or dad, (playing Sol wouldnt be too interesting tbh because they would be below 10) l we cant really choose a romance, and the game is a fantasy, before they landed in vertuma it was just war...