The Heavenspan Realm, also known as Arch-Emperor Realm, is the Realm where the first 1000 chapters of A Will Eternal happens. The highest cultivation base was Quasi-Celestial.
The Heavenspan Realm is a Realm created within the statue of a powerful expert known as Arch-Emperor. This Realm was ruled by the Arch-Emperor's descendants until a powerful cultivator with great talent decided to rebel. That cultivator name was Daoist Heavenspan , who would later on be referred as the Celestial. He stole the Live-Forever Codex from the Arch-Emperor Dynasty and led many cultivators to the Heavenspan Realm, establishing the Four Great Sects in the Upper Reaches Region.
Since that rebellion, the Heavenspan Realm was divided in two factions, the Heavenspan Continent cultivators, under the leadership of Heavenspan Daoist, and the Wildlands cultivators, under the leadership of the Arch-Emperor Dynasty.
Ruled by the Heavenspan Island and the Four Great Sects. Ultimately, the entire continent is under the Celestial's command as the Four Great Sects Patriarchs are his disciples.
Ruled by the Arch-Emperor Dynasty and overseen by the Hell-Emperor (the Gravekeeper). The Four Heavenly Kings have the highest amount of authority under the Hell-Emperor and Arch-Emperor and are equivalent to the Heavenspan Continent's Four Great Sects Patriarchs.
In the Heavenspan Realm, it is much more difficult to reach Celestial Realm than in the Eternal Continent. Because of that the highest cultivation base achievable in this Realm is Quasi-Celestial. The only way to become a true Celestial in the Heavenspan Realm is to practice the Arch-Emperor Dynasty's Undying Live-Forever Technique to the Mahayana realm. Otherwise the only way would be leaving the Heavenspan Realm.