In the Cultivation World, there was actually a very straightforward way to judge a demon beast's rank.
That was to look at its size!
A Tier 1 beast was around ten feet tall.
A Tier 2 beast could range from twenty or thirty feet to seventy or eighty.
But once it reached over a hundred feet, it was basically a Third Order Demon King.
As for a Fourth Order Demon Emperor, comparable to a Human Race Nascent Soul, its body was often over a thousand feet long. It could sit or lie like a mountain, and stir up gale-force winds with every step.
That was why the sight of a Great Demon traveling—Demon Qi spreading and demonic winds sweeping across the land—was so terrifying.
The reason demon beast realms were linked to body size had been deliberately studied by a predecessor.
The conclusions could be summed up in three points:
First, a large body intimidated one's kind and allowed it to seize territory. All beasts instinctively pursued greater height and bulk.
Second, demon beasts had evolved from Desolate Beasts by taking up the Human Race's path of cultivation. In essence, Demon Wasteland and Desolate Beasts were inseparable, and Desolate Beasts excelled at Body Tempering, seeking to evolve mountains, rivers, the sun, and the moon from their own bodies. The Mirage Dragon Cave Heaven that Luo Chen had seen, and even that enormous Gobi Desert in the Fallen Devil Land, had both been formed from powerful Tier 5 Desolate Beasts. Even after switching to the Human Race's cultivation system, demon beasts still retained this instinct.
The third point was rather discriminatory.
According to that predecessor, demon beasts were born dull-witted and lacked mastery of the Human Race's methods, so their Qi Refining was exceptionally crude.
They could not meticulously temper and