Heavenly Sovereign (天皇, Tiānhuáng) was the first Chinese legendary king after Pangu's era. According to Yiwen Leiju (藝文類聚), he was the first in Three Sovereigns.
Biography
According to Book of History (史記),
His greatest achievement was suppressing all the chaos, divided the world to many tribes with choosing the best person to rule his tribe.
References
Heavenly Sovereign Wikipedia(Text) CC BY-SA