Who needs airline miles when you can earn in-game rewards?

That's the idea behind a partnership between Riot Games and American Express.

The New York credit card company announced this week that it has integrated its prepaid debit accounts with the reward system used in Riot Games' popular online title "League of Legends."

Cardholders will earn points when they deposit money into their accounts and make purchases. The points can be used to purchase in-game extras to customize characters.

AmEx will also distribute customizable debit cards with "League of Legends" characters printed on the front.

"Riot Games is passionate about serving their players and giving them avenues for enhancing their gaming experience," Stefan Happ, senior vice president of U.S. payment options for American Express, said in a statement. "Together we've been able to create a great co-branded product with a unique rewards program that will help 'League of Legends' players earn Riot Points whenever they use their card to make qualifying purchases."

AmEx will also become a sponsor of Riot Games' "League of Legends" tournament series, known as the League Championship Series. The tournament culminates in a world championship to be played at the Staples Center in October.