Mr. Logan, who was bored in the real world, came to a magical world, where he and a group of motor oilers would travel through various fantasy worlds.
Everything was beautiful originally, but since he accidentally cheated a happy young boy, when the boy had to transform into a magical boy in order to survive, everything began to change quietly.
For example, if you accidentally fall apart...
By the way, because I like the game Soul Sacrifice very much, the protagonist of this book is about the mage exchange of Avalon.