The Ninefold Titan Physique Scripture was something he handed over to a mortal back when he traveled to this mortal world.
Other than rescuing Qing Lan, he also imparted some techniques to those he liked.
It had been many years since then, so the technique gradually deteriorated or became lost in the process.
In the end, what remained in the original was some flawed copy of the technique by someone else.
Lin Loi happened to stumble across the technique in a secret realm. Since this technique was way beyond the mortal world's comprehension, it was only natural that they would never understand the consequences of practicing this flawed technique.
Sure, one's cultivation base would definitely improve by leaps, and even one's body and strength would be tempered.
Unfortunately, without the proper method, their body soon develops impurities that need to be cleansed. And these impurities were difficult to remove once formed.
