While Yale's incarnation created that world surrounded by light, more than a thousand years passed since Yale's group departed from the world where Yale's disciple was facing the Life and Death Trials.
After the Life and Death Trials ended, Yale noticed that his incarnation didn't come back, so he guessed that his plan was a success and just waited for his incarnation to return with news someday.
Those thousand years had been relatively calm since there weren't too many people who would trouble a group with three Essence Gods.
Those too weak were just seeking death, and those stronger usually had a good understanding of the factions, so they wouldn't act without verifying the other party's identity.
Of course, those allied with the invaders would try to seek problems at any chance if they discovered them, but they were invaders, so they were a minority even counting their allies, and there was no way they could find Yale's group easily.
