If you climb up the Youkai Mountain and into the sky, you can reach Heaven, the home of the celestials which is famous for its peaches. It is located somewhere in the Netherworld, separate from the mortal world.

Celestials are humans who undergo rigorous training to ascend to Heaven. It might be a bit boring for those who have not experienced the bitterness of war, poverty, and other mortal sufferings.

Living in Heaven leaves you out of the circle of reincarnation. You could call it an entirely different world.

Those who become celestials while living are only extending their lives unfairly. If they are attacked by somebody from Hell, they would end up meeting their death...

If you become a celestial, you can eat all the peaches you want, but you cannot become a celestial without abandoning earthly desires like "I want to eat peaches!"―it is quite the odd dilemma.