The biggest difference between the Immortal Realm and the Human Realm, aside from the matter of Spiritual Energy, is the issue of the Heavenly Dao Laws.
In the Immortal Realm, the Heavenly Dao Laws are more complete.
It is comparatively easier for humans and animals to gain sentience and achieve enlightenment.
Originally, when the Heavenly Dao first unfolded, there was no Immortal Realm.
There were only the Human Realm and the Netherworld, like two mirror surfaces.
Later, through repeated cataclysms, a Saint forcibly divided the Human Realm in half.
Every battle took place in the Human Realm, leaving it devastated and fragmented.
Meanwhile, the Immortal Realm became a preserve, with various laws still maintaining the initial state of the Primordial Wild.
