Three days later, the sky was filled with thunder and lightning. A tremendous storm broke out. Rain fell incessantly and the flood waters rose; huge waves swept across the earth and the entire human race was destroyed. As the flood began, the Thunder God's tooth transformed itself into a boat. Safe aboard this vessel, Fuxi and his sister rode the waves and drifted with the tides. Only when the waters had subsided did Fuxi and Nuwa realise that they alone had survived the desolation. When they had grown into adults, Fuxi and Nuwa became husband and wife in order to bear descendants and establish a new human race.
This second story reflects the custom of intermarriage between blood relations in ancient China. It also shows why Nuwa is known as the mother of the Chinese nation.
It is said that there were no men when the sky and the earth were separated. It was Nuwa who made men by moulding yellow clay. The work was so taxing that her strength was not equal to it. So she dipped a rope into the mud and then lifted it. The mud that dripped from the rope also became men. Those made by moulding yellow clay were rich and noble, while those made by lifting the rope were poor and low. - from Tai ping yu lan