Apart from its limited coverage and inability to capture sound, another issue was its poor penetration when faced with actual physical obstructions like mountains and oceans.
It could be used to observe formidable beings from the Ninth Heavenly Layer, such as Chu Xiuyuan and Ye Yan.
However, it was best if the target was preoccupied, with their focus on a Heavenly Principle expert opposite them.
If used during leisure time, the Great Celestial Mirror's intense scrutiny of a Ninth Heavenly Layer expert could still risk detection.
This was especially true for Martial Tao experts or cultivators renowned for their extremely keen perception and sensory abilities.
If a Ninth Heavenly Layer expert was particularly adept at concealing their tracks and deliberately hid, the Great Celestial Mirror would also have difficulty finding them.
These are all areas for future improvement… Lei Jun silently noted.
