As a woman, the Nine-tailed God Emperor held the position of a nation's ruler, naturally not to be underestimated in her abilities. However, in recent millennia, she was deeply engrossed in cultivation, rarely managing the affairs of the Divine Country. This resulted in some ambitious lords growing stronger and eventually breaking free from her control.
If the Imperial City hadn't been destroyed, the Divine Country would not have any issues. But as it stands, the Imperial City is gone, and the God Emperor's various armies have either perished or disbanded while fighting against the star beasts, leaving only the Imperial Guard. To put it bluntly, the power of any random city is stronger than that of the current Imperial Guard.
It's normal not to submit.
The Nine-tailed God Emperor just never expected Luo Shuang, whom she always valued, to betray her.
