To reshape the bloodlines of the Human Race, the blood essence of a Saint like Empress Nuwa alone is not sufficient; the other two sacred artifacts of creation must also be enhanced accordingly.
For instance, when Empress Nuwa created humans, the Soil of Rest she used from the Nine Heavens was a High-grade Innate Spiritual Treasure, so if Jiang Chen wants to reshape the bloodlines of the Human Race, he must use Soil of Rest from the Nine Heavens of the Innate Treasure grade, and the same goes for the Three Lights Divine Water.
However, Jiang Chen already possesses this treasure, the Three Lights Divine Water, in his possession.
The Three Lights Divine Water is the combination of three types of extremely toxic substances, Sunlight Divine Water, Moonlight Divine Water, and Starlight Divine Water, forming an Innate Divine Water, one of the ten great Innate Waters of the Prehistoric World.