Having said this much, I looked at my master, waiting for him to continue. Since I didn’t want to trouble anyone else later and had no idea where else to look for such information, I decided to press him. "Master, tell us about the 12th and 13th layers as well! And what exactly does it take to achieve Heaven-Grade Foundation Establishment?"
My master recognized my potential, sensing that I might have some ambition, though he sighed at the fact that I was born in the wrong era. "Consider this an expansion of your cultivation knowledge; just listen," he said. "In the old days, when the world was rich in Spirit Qi, the 12th layer required a peak sixth-grade spirit vein. As for the 13th layer, it apparently required a mid-grade seventh-grade spirit vein. Once a spirit vein reaches the seventh grade, it undergoes a fundamental change. The Celestial Dynasty's spirit veins today are maintained at the level of low-to-mid seventh grade. The highest-grade spirit vein in our Sect is only level five."
"As for Foundation Establishment, it is essentially the continuous accumulation and subsequent refinement of Spirit Qi. Earth-Grade Foundation Establishment is achieved by consuming various heavenly treasures. Human-Grade Foundation Establishment is what everyone gets from the Foundation Establishment Pill. People also call the Human-Grade method 'waste foundation,' meaning that, essentially, one is a lost cause with no hope of reaching immortality."
Chapter 360