Dark World (Dragon Quest Monsters: Joker 2)
From Dragon Quest Wiki
The Dark World is a maze of corridors with a circular hub in the center found in Dragon Quest Monsters: Joker 2. It is the tenth and final area accessed in the game.
Description
At the rear of the chamber of Leonyx lies the portal to the Dark World. Leonyx will not open it until the player has proven his overall toughness by besting him in battle.