While the power leveling system of colored humans involves sword level cultivation and mana convergence stage.
Variant humans are divided into classes and tiers.
While there are different colored humans in existence. There are only one species amongst each colored humans.
But variant humans are different. Especially demonic variant humans.
Having twelve classified species of each demonic variant human group. Goblins, Trolls, Beastmen, Vampires and many more.
And this classified species are divided into two, six higher class species and six lower class species.
Each species having a specific kings known as boss monsters and this boss monsters are recorded as tier monsters.
Just like the E-tier Snow Goblin Caden faced. It was a boss monster and also the king of the Snow Goblin group he had encountered.
Tier boss monsters evolves beyond the limitations of their species.
