Quote Originally Posted by Fayt1203 View Post
Well they made a mistakewhen the made the 13 into the void so it did not join the source

if i remember correctly I can be wrong need to dive deep into the story and the lore again
https://finalfantasy.fandom.com/wiki...mbral_Calamity

Assuming this is accurate, the worlds rejoined in order were: 5th, 12th, 2nd, 3rd, 6th, 10th and 7th.