Surpassing All Tribulations

In the Golden Age of theLinhao Empire, the Lightning Saint of the mighty Lei Clan is murdered and betrayed by his own disciple. After decades of attacks on his very own foster clan and the joint union of the other clans, the newly dubbed Lightning Demon is finally killed by the combined forces of the other elemental Saints. 100 years later, a young boy is found near the historical battle site of the saints by a declining noble clan. Who is this boy and how is he related to the incident that rocked the Linhao empire?