Originally Posted by
SirPrizes
I just finished the game recently, and I got the impression that Kuja did in fact destroy the crystal, and all life was in the process of ending before Zidane challenges Necron. The moans that you hear in the background are all the suffering souls crying out in pain, yearning for death to end it. Zidane's will to live and the party's will to save Gaia is the only thing that stops this from happening. In other words, the final battle takes place in a tiny window of time where there is still time to stop the nothingness that Necron talks about wanting to bring.
This is all probably only happening in the Crystal World though, and things in Gaia are probably continuing as they normally do meanwhile.
I also got the impression that those you don't choose to be in your party basically die, but their souls merge with your party members in order to help with the final battle (or maybe it takes the strength of two of them just to reanimate one's body).