Darkness ( Duel World ) Darkness is the fourth Duel world in " Yu - Gi - Oh ! World Championship 2008 " . This world introduces the player to Tag Duels . Neo - Spacian Dark Panther will explain the mechanics of Tag Duel to the player and also puts the player in a practice Duel to demonstrate . After this , he ' ll become the player ' s tag partner ( this can be changed if the player has beaten any Duel spirit at least 10 times , excluding other tag Duelists and stone tablet monsters . Any Duel ghost the player have downloaded will also work ) . Duel Spirits teams . Now , this place has several teams waiting for the player . The player defeating each of them 5 times will unlock the respective team in the newly added " Tag Duel " mode in World Championship Mode . There ' s Renge , Gatekeeper of Dark World waiting at a corner . The player talk to him , and each time the player do so the player well find itself in a Tag Duel with some of the Dark World denizens , and the player well also have to ante a card with " Dark World " in its name . The teams are : Also , since the player is wagering a card , the player well also get a Dark World card each time the player defeats a team . Now , once the player is done beating these three teams , the player will Duel every team available once more ( appears that they have been brainwashed ) , and then a castle will appear . If the player went back to Darkness , Nurse Reficule the Fallen One will be there too , and she may randomly change the appearance of the player ' s face for 500 DP ( the player itself cannot change the result ) . Treasure chest . Once in a while , there will be a treasure chest around the area and the treasure chest may be a trap . The treasure chest can either contain nothing , DP , card , or be a Dark Mimic LV3 . The player must be careful to not fell for it . Castle . The player visit it , and the player will be greeted by Gogiga Gagagigo and Mobius the Frost Monarch . After the player beat them , and the player will afterwards be challenged by Vampire Lord and Vampire Lady . Defeat both teams and they unlock themselves in World Championship Mode . Alien Infiltrator arrives , grumbles about the player undoing of the brainwashing , and disappears into the sky . Sky . The map has expandeded - the player heads up into the skies and takes on more teams . UFOroid also appears on occasion . Correctly guess the symbol it is thinking of and it will give the player a card . After beating each team once , Alien Infiltrator and Alien Shocktrooper will challenge the player to a brainwashing Duel - this one is computer - controlled . It may take the player a few tries to beat them . After the player beats them , they unlock themselves , and reveal the gate to the next world . Gate . When the player goes to the next gate , the player is to face the guardians , Dark World Guardian - Gigori and Underworld Guardian - Moley , and their five Deck combinations . The player beats three to proceed , and beats five to unlock Aster Phoenix in World Championship Mode . Stone Monument . The stone monument will appear once the player has defeated every team five times each . The stone monument has a carving of Vennominaga the Deity of Poisonous Snakes . The player needs to summon Vennominaga and use the effect to win the Duel , in order to unseal it . Beating the monument will unlock Professor Thelonious Viper in World Championship Mode .