And according to the Golden Immortal Avatar from the Monster Immortal Realm, this Devil Immortal Illusion should be a Semi-Saint Illusion.
A Semi-Saint must be above the Great Luo.
The Great Luo isn't too finely divided.
Early stage, middle stage, late stage, and peak—these phases are enough to clearly differentiate between the realms.
As for Perfection, strictly speaking, it isn't a realm but a level one can reach to break through to the next major phase.
In terms of battle strength, there isn't much difference between peak and Perfection.
It's more about the difference in power accumulation, state of mind, and condition.
In terms of fighting capacity, one at the phase of Perfection can withstand a longer period of battle than one at the peak.
After all, their accumulation is somewhat richer.