Everything Gao Xuan saw was transformed by his own power.
The Heaven-Confusing Demon Emperor couldn't actually see Gao Xuan's illusion either. If it were a low-tier cultivator, he naturally could enter the opponent's illusion, play a role, and guide the changes in the illusion.
Gao Xuan's divine soul body was nearly perfect, and the Heaven-Confusing Demon Emperor didn't have the courage to enter Gao Xuan's illusion.
Any slight mistake would alert Gao Xuan to the abnormality, thereby awakening him from the illusion.
The illusion did not cause any substantial harm to Gao Xuan. The Heaven-Confusing Demon Emperor could only take advantage of Gao Xuan's fall into the illusion to harness the power of Mengze Lake, creating an eternal Illusory Dream Immortal Realm for Gao Xuan.
Through the passage of time, it could gradually erode Gao Xuan's divine soul, eventually killing him.
Of course, this requires patience.
