Why didn't Gu Nan die for two thousand years?

During the Three Kingdoms period, some people could see Nanjie's life, but God didn't know that in all Nanjie's explanations, there was a stronger or higher existence than Heaven.

Tiandao first appeared in front of Nanjie because she had a mole in the corner of her eye, indicating that Tiandao was gone.

When Gu Nan climbed out of the soil, the descriptions of internal forces emerged in an endless stream, and even the circulation could be improved by itself (the meridians were unimpeded when Gu Nan was instilled with internal forces at the beginning of Tian Lei), so this is probably the reason for Gu Nan's longevity. If so, it means that it is very likely that someone has reached this state before.