The humans were banished to the very bottom stratum realm of their universe, where the spirit qi and soul qi were scarce and life was harsh. They were forced to adapt to a new environment, one that was not as bountiful as the divine realm of the Chaos Tree. They were forced to survive with the limited resources available to them, and they were forced to learn how to live without the guidance of their creator, The Chaos God Tree.
The humans soon realized that they could not summon the ancient beasts as they had done in the divine realm. The spirit qi and soul qi were too weak to sustain such powerful creatures. Instead, they had to learn to form contracts with the creatures of this realm, the elemental animals. These animals possessed powers of metal, wood, wind, fire, earth, water, ice, shadow, poison, light, and darkness, and could be tamed and controlled by the humans through a contract.
The humans formed a new society, one that was based on the art of contracting. They formed guilds and organizations that specialized in different types of elemental animals. Some focused on metal creatures, others on wood, and others on fire. They learned to harness the powers of these animals and use them to survive in this harsh realm.
But as time passed, the humans forgot about the divine realm and the Chaos Tree. They forgot about the ancient beasts and the sins that had led to their banishment. They focused on surviving in this new realm and building a new society. They passed down their knowledge of contracting to their children, and it became a way of life for them.
The humans' society thrived, but they were forever separated from the divine realm and the Chaos Tree. They were forever relegated to the bottom stratum realm, where the spirit qi and soul qi were scarce and the ancient beasts were nothing but a legend. They were but only a shadow of their former selves, and their power was limited to the elemental animals they could contract with.
And so the humans' society lives on, in a realm far removed from the divine realm of the Chaos Tree and the ancient beasts. They live in a realm where only the elemental creatures that they form contract with exist,a realm of shadows and memories, where the legends of the Chaos God Tree and the forgotten realm are all that remain.