The Pain Penance, often called the Earth Tribulation, was meant to test the strength of the body.
It was said to tear apart one's flesh and bones, forcing every fiber to rebuild itself under unbearable pain.
It was also said that the reason there were only eight or so Core Formation Lords in the Dadangar Subcontinent—and why so few Foundation Experts managed to enter the Core Formation Realm in general—was because of this test.
Those who failed often died terrible deaths as their bodies destroyed themselves from within.
The process was like watching a watermelon burst in slow-motion videos, except there was no hammer, and the watermelon simply imploded on its own, sending its flesh everywhere.
Because of this, most late-stage Foundation Establishment Experts never even attempted the Core Formation breakthrough. The risk was too high, and the rewards too uncertain.
