The World Level is a realm of cultivation that exceeds the level of Gods.
A World level expert is an invincible existence in a Great World, able to rule over everything, and they can transcend the Great World to traverse the Primal Chaos plane.
This is the minimum level needed to walk freely in the primal chaos plane outside a Great World without using a ship or external help.
The two Ancestral Gods of the Ancient Race were at this stage. They had the Ancestral Eyes of Heavenly Law and the Ancestral Eye of Illusion.
It should be possible to reach this level by fusing sets of Laws perfectly to produce the Law of Primordial Chaos.