Previously, three Title Douluos of the Xingluo Empire had traded their lives to detonate their own Soul Cores, creating the opportunity for Xuanji Douluo to damage Death God Tower and release the hundreds of thousands of wraiths trapped within.
Although the Sun Moon Empire was currently advancing triumphantly through the Heavenly Soul Empire, converting dead souls into wraiths took time.
The wraiths currently inside Death God Tower essentially constituted the final reserve accumulated by the Holy Ghost Cult over all these years of its existence.
Chapter 997