After K.S.S. Token took all of Stewart's fantasy stories and became famous, Stewart had to come up with new material for his novels. He came to the caverns for inspiration. The boss promised him all of the magical stories he could ever imagine, as long as he portrayed the boss and her allies as heroes. He plans to announce his new novel at Dra-Con.
Each mastery level adds another card to the cardpool for defeating Stewart. Each of the bronze, silver, and gold mastery levels unlocks a new card, while it takes all three diamond and onyx levels to unlock a single card.