The Purple Sun Writes, the Red Moon Returns to the Soul

The protagonist decided to commit suicide due to the accidental death of his sister. During his suicide, he saw the purple sun crossing the book and discovered that there was an unknown side of the world. He decided to explore. After completing the first mission, he understood the concept of the world in the book and learned that after completing 21 times of traveling through the book, any wish can be fulfilled. In order to resurrect his sister, he decided to start his journey through the book.