Immortals attain longevity, thus forsaking reincarnation.
Before the Underworld came into existence, the Immortal Realm possessed the Six Paths of Reincarnation, where birth, aging, sickness, and death were governed by natural laws.
Then, the Creator harbored a dream of forging a perfect world, keeping all the best things right here. Thus came the Immortal Realm, a super-great plane.
Chapter 1841