Pan Gu was the leader of the Ancient Gods. He led the first war against the Ancient Dark Ones. When Hei Long, ended the war against the Ancient Dark Ones, Pan Gu and the other Ancient Gods feared his power and tried to kill him.
Even, as Hei Long, was exhausted in his fight against the Ancient Dark Ones before, his power was far too great and Pan Gu and the other Ancient Gods were killed by Hei Long, later known as Tian.
The transcended vigor of Pan Gu was later reborn in form of the Elder Sage Shen Yen.
He was the last Ancient God to die by Tian's hand.