Colorist

A world stained black. Driven by the Black Witch, humanity is forced into a vast city where light and color converge. To reclaim the world, humanity continues its pioneering efforts, and a boy named Kay aspires to join the expeditionary force. But he’s rejected because he is colorless, lacking any hue. Then one day, through an unexpected incident, Kay gains the color black....

(Source: Naver, translated)