Above the Sky: the Hidden Second World

In the distant past, in an unknown era, there lived a strange race in the sky. According to legend, they lived on the clouds and came down from time to time to plunder the human race. The ancestors of the human race called them "the sky-stealers" or "the sky-steers". Second, they can also grow wings and fly. They have strange spells and have caused huge losses to the ancestors of the human race. Then the ancestors captured an old man of the Sky Pirates, learned the secrets of the spells, and developed human spells. Soon, the profession of "anti-air mage" appeared in people's sight. The story takes place hundreds of years later...