Blizzard’s first free-to-play game is showing that it has staying power.

Hearthstone: Heroes of Warcraft is charging up the top-grossing charts in several crucial mobile-gaming markets, according to data-tracking firm App Annie. On the iPad (which has a separate chart from iPhone), the collectible-card game is the fourth highest-grossing game in South Korea. It is No. 9 in China, 12 in Canada, 22 in the United Kingdom, and 22 in the United States. These nations are many of the biggest spenders when it comes to games on iOS and Android. In Japan, the top country for mobile-gaming revenue, the game is No. 100. That is up 65 spots from the previous day (App Annie updates daily). With spending on mobile platforms expected to reach $21 billion through the last 12 months, Hearthstone’s surge in the top markets could really help Blizzard’s bottom line.

The card battler isn’t just doing well on iPad. On the Android charts (which combines tablet and phone sales), Hearthstone is also earning a good amount of cash. That’s important because Android has a huge market share in important places like China, Japan, and South Korea.

It is No. 31 in China, 37 in the U.K., 68 in the U.S., and 199 in South Korea. Those numbers should go up even further early next year when Blizzard released the phone version of Hearthstone. That will make a big difference in places like South Korea, which has a huge number of Android-phone owners.

Hearthstone’s performance is on the upswing. After debuting on iPad in April, it struggled to maintain a top place on the important grossing charts just eight weeks later. But Blizzard has reinvigorated enthusiasm for the card-battler by releasing the Android version and updating it with new content.

In early December, Hearthstone got more than 100 new cards as part of the Goblins vs. Gnomes expansion. Players can buy booster decks filled with cards from this add-on, and that is likely playing a big part in Hearthstone’s improved performance. People who like Hearthstone returned to check out the new content, and they are probably getting hooked all over again.

None of this takes into consideration the PC version of Hearthstone, which has a huge dedicated audience born out of fans of Blizzard who have followed the studio’s games for years.