Konami launched Yu-Gi-Oh! Duel Monsters: Ultimate Card Battle as a free-to-play title on Nintendo 3DS, and the company announced that the game has topped one million downloads since it’s launch.

To celebrate the milestone, the game started a limited time boss fight yesterday, featuring Marik Ishtar. This event will carry on until December 4, 2016.

Yu-Gi-Oh! Duel Monsters: Ultimate Card Battle is available in Japan for Nintendo 3DS. The game is expected to release outside of Japan, but a launch date or window has yet to be announced.