The secret angel of Bump World is the X angel-Zander. Zander is the original S-class heavy hitter in the game "Bump World", and he is the X angel under the wisdom angel, one of the seven angels. As a teenager, he was the apprentice of the ultimate knight Phyllis and the brother of Amisius. Because of his cleverness, he has attracted much attention and is the heir to the knight in everyone's mind. Later, he defected from the Knights Templar, wandered among countless planets, and finally became an X angel.

Concave-convex world is a cartoon created by Kai Chuang Society. The book was published by Jiangsu Phoenix Literature and Art Publishing House and Yangcheng Evening News Publishing House, and the electronic version was published by Netease Comics, Buka Comics, Weibo Comics and Quick Look Comics.