Shares of Activision Blizzard Inc. (NASDAQ: ATVI) jumped as much as 21 cents Thursday after the video game maker announced the release date of Diablo III, the latest release in its popular role-playing game series.

Activision closed up 13 cents to $12.46. Diablo III will be released on May 15, more than a decade since its predecessor, Diablo II, hit stores.

Fans of the game were undoubtedly gleeful at the announcement, but investors may be more cautious as the company faces declining revenue from its World of Warcraft series, which has lost subscribers in recent quarters.

Activision's Blizzard unit is implementing a real money auction house for players, allowing them to trade virtual goods for currency that is redeemable for real money. Blizzard will take a flat fee for each transaction in an effort to extract a new revenue stream, but it's uncertain if revenue will offset the company's declining World of Warcraft subscribers.

Shares are still down from $13.93 on Nov. 8, 2011.