The following novels all had plots where the main character had the Dungeon System: One Piece: I Have a Dungeon, The Archmage of the Other World, The Invincible Ghost Sword of the Other World, The Light of the Soul, The Sword of the Soul, Live Stream in the Dungeon, The Dungeon Invasion of the Dungeon, The Dungeon Sharpshooter Begins in Zuan, The Dungeon Master's Journey to the Other World, and The Dungeon System. I hope you like this fairy's recommendation. Muah ~😗