Mistakes that Rex made in the past, its effect became apparent as of this moment.
At least for now, the bad effect became visible to him.
Due to the System Relaying Bet Quest that was forced out of him by the Fifthborn, he wasn't able to exploit the onset, of the Second Breath. He relied on Flunra to make the preparations for this phenomenon.
Had this happened during the First Breath, they would've been fine with only Flunra's help.
But unfortunately, this happened during the Second Breath.
Since the First Breath had reached its end—all Elders of the Supernaturals had already been awakened completely. Rex had dealt with the Elders before, but this time, the number of the Elders would increase by a lot.
Elder Nolacula, Tilrith, Enima, and the others were not the only surviving high-rank Elders.
More of them were now awakened and ready to tackle the new era.