The second possibility is that these Ultimate Dark Entities didn't make it, or they died.
The World of Calamities was created when the Endless Calamity invaded the Real World. So, where did the Endless Calamity come from before the invasion? Why did it invade the human world? What were its origins?
Perhaps, the reasons why these other top ten Ultimate Dark Entities did not appear in the World of Calamities are hidden within these three questions.
Casio now has too little information and can only make one guess.
The third possibility is that these Ultimate Dark Entities were absorbed by Xiadu.
Why was Xiadu so powerful? Even before being sealed, it was the concept of a disaster, intangible, colorless, supremely powerful! Maybe Xiadu was the monster produced by the fusion of those top ten Ultimate Dark Entities? Or perhaps Xiadu absorbed them to make itself invincible. The existence of Xiadu's true form was sealed behind the Three Gates of Heaven, within the Three Origin Seas.
