Call this a game-changer. Activision Blizzard, the company behind the juggernaut Call Of Duty and other huge video game franchises, is set to acquire Candy Crush maker King Digital for $5.9 billion — creating a new leader in the ever-expanding mobile gaming space. The combined entity will boast more than 500 million active monthly users in 196 countries.

While Activision Blizzard is an industry leader in the console and PC gaming space, the deal makes it an immediate top player in mobile.

The Santa Monica-based company — whose franchises also the WarcraftTony Hawk’s Pro Skater and recently revived Guitar Hero –– will pay $18 per share for King Digital, a 20% premium over the latter’s October 30 closing price. King Digital will continue to be led as stand-alone unit by CEO Riccardo Zacconi, Chief Creative Officer Sebastian Knutsson and COO Stephane Kurgan.

“The combined revenues and profits solidify our position as the largest, most profitable standalone company in interactive entertainment,” Activision CEO Bobby Kotick said in a statement. “With a combined global network of more than half a billion monthly active users, our potential to reach audiences around the world on the device of their choosing.” Added Zacconi, “We will combine our expertise in mobile and free-to-play with Activision Blizzard’s world-class brands and proven track record of building and sustaining the most successful franchises, to bring the best games in the world to millions of players worldwide.”