So, the story began in the Middle Age when strong practitioners from different worlds fought for the World's Source.
During the Middle Age, the main space had originally been vast and stable, but it was constantly ruined and split due to a devastating war. Inner worlds where people still existed were spaces that had been split due to the war in the Middle Age. Needless to say, the inner worlds which still existed were rare because most of the spaces had been destroyed in the war. Even if they were not destroyed, they would have gradually collapsed as time passed.
Inner worlds that still existed were as rare as hen's teeth when compared to the number of them that there had been during the Middle Age.
The Peng Lai Immortal Realm was not a space split due to the war but was still a part of the main space. It had never left the main space.
