Yu-Gi-Oh! Nightmare Troubadour Cheats

You must have your GBA Yugioh game named Yu-Gi-Oh!GX Duel Academy inserted into the GBA Slot of your Nintendo DS. Start up your Yu-Gi-Oh! Nightmare Troubadour and you shall get 3 wing Koriboh cards. The card that Jaden Yuki uses in the tv show.

You must progress through the game until you get the Marik. After you duel him a lot, and if you have either Slifer or Obelisk in your trunk, he will ask to trade you for his Ra.