A World Ruled By Colours

On Earth, every human is ranked by a color. From the lowest gray, to the highest white gold. After birth, every human is marked with a color on their right arms. Our MC, Jun Zihao, was born marked with the color black. The color black had never existed in the rankings, thus everyone around assumed that black was the lowest color, lower than gray. Due to that, people mock him and bully him constantly.
One by one, revenge is made.
Mysteries are unraveled.
Answers are revealed
How will Jun Zihao perceive through the hardships, and find the true meaning of his color?