All the laws of heaven and earth are composed of the two qi, clear and dull, and the Five Elements: metal, wood, water, fire, and earth.
According to the scriptures of cultivation taught by Professor Yu Hua, the reason cultivators can perform Flying Escape is by borrowing the clear qi. All techniques of flight are due to the clear qi, while on the contrary, earth escape techniques utilize the dull qi.
Going further, any magic skill that has beautifying effects employs the clear qi, and anything that arouses a cultivator's desires uses the dull qi.
Most people Gu Wen saw were chaotic, containing both clear and dull qi, and all five elements. On this Residual Soul, he saw pure dull qi.
He guessed, "Do you come from the underworld?"
"Saint Venerable has eyes that recognize the genuine from the false."
"I would like to ask about some matters. Could I trouble you to enlighten me a little?"
"Please speak, Saint Venerable."
