The Star Alliance was expanding. After taking a star domain, it generally needed to complete two crucial steps before it could merge that domain into the Xiantian Spiritual Treasure, the Celestial Star Array Diagram.
The first step was to seize the star domain's Central Black Hole and establish a Star Domain City upon it.
That was what the Star Alliance had done when it first expanded into the Heavenly Demon Star Domain, establishing Heavenly Demon City atop the domain's Central Black Hole.
When Liang Ji and the others had seized the Heavenly Demon Star Domain, they had likewise first established Heavenly Demon City atop its Central Black Hole.
The Central Black Hole at the heart of each of the Star Alliance's thirty-five star domains had a Star Domain City established upon it.
Yinghai City, Penglai City, Manggu City, Gemini City, Taihao City, and so on.
These Star Domain Cities had all been specially refined. Each contained a Celestial Star Pivot forged by Taihao Star Palace, which was crucial to suppressing a domain's Star Chart Great Formation. It was also a key Formation Eye, a node, for merging a star domain into the Celestial Star Array Diagram.
Therefore, no matter which star domain the Star Alliance Army attacked, its first objective was to seize that domain's Central Black Hole.
As long as the Central Black Hole remained unconquered, the Star Alliance could not be said to have completely taken that star domain.
Back when the Spirit Realm and the God Realm had yet to merge, the Star Alliance had counterattacked the Spirit Realm. Led by Ninth Rank Star Lords, the Star Alliance Army had invaded the Spirit Realm and entered multiple star domains, including the Thunder Marsh Star Domain and the Black and White Star Domain.
But the Star Alliance Army