Half a clear breeze

Chu Xuan transmigrated to a fantasy world and became the young master of a powerful family. He was rebuked for misbehaving just because he sneezed during a banquet. As punishment, he was banished from the ancestral mansion and was relocated to a remote residence.
He did not mind the punishment at all. He just needed a spot that could allow him to be a shut-in. With the system that would allow him to grow stronger by being a shut-in, the longer he stayed indoors, the more powerful he became.
After being a shut-in for a day, he was rewarded with the Indestructible Body Technique.
After being a shut-in for a month, he was rewarded with the Immovable Mountain Technique.
After being a shut-in for a year, he was rewarded with the Yuxu Celestial Scripture and 100 years of cultivation.
After being a shut-in for 10 years, he was rewarded with the Chaotic Indestructible Body and the Bell of Chaos.
…
Chu Xuan declared, “No one can make me leave my home. I like being a shut-in!”

I Stayed At Home For A Century, When I Emerged I Was Invincible

The sariras were formed from the Buddhist power of Buddhist disciples after they died.

To Buddhist cultivators, they were supreme treasures.

Those who could form sariras had to have a deep understanding of Buddhist cultivation techniques, and their cultivation levels were not low.

The larger sarira had been left behind by a Heaven realm Buddhist disciple.

The five smaller sariras had been left behind by Supreme realm Buddhist disciples.

It could be seen that the Buddhist sect of the Demon Zone had been embroiled in great conflict. Even a Heaven realm Buddhist disciple had died.

After these Buddhist disciples died, they actually left behind sariras. This undoubtedly proved what Demon Buddha had said. They seemed to be dead, but in fact, a wisp of their soul had already returned to the Nirvana World.

As for the other fallen Buddhist disciples, why did they not leave behind any sariras?

The Great Daoyuan Calamity