Beat It Out
The concept of caste didn't exist in the society of the Demi-Human. Each Demi-Human had a status which was based on their battle prowess and their innate talent but everyone treated each other equally. Status didn't matter much because they considered everyone family. Still, one could easily spot the difference between Nobles and commoners.
Those who managed to climb to the rank of Nobles were powerful Demi-Humans. Nature favoured them—they were born with an absurd innate talent, making them ahead of everyone else. While their talent made them stand out, there was another thing that made them stand out—their appearance. Stronger Demi-Humans resembled humans more than most of the population did.
It had nothing to do with how far they had evolved but with how well they could control their Beast traits. They could control their emotion better but they were still hot-headed like most of the population were.