KONAMI’s latest, free to play 3DS Yu-Gi-Oh! game the Yu-Gi-Oh! Duel Monsters reached the 1 million downloads in Japan. This title released on July 6, 2016 on Nintendo 3DS as a digital only but free to play game based on the popular Yu-Gi-Oh! series.
To celebrate the 1 million downloads, KONAMI published on the official website of the game which unlocks a new campaign. In this campaign you can play against Marik Ishtar. You can find the code in here: http://www.konami.jp/yugioh/card_battle/code/