Blizzard's Warcraft franchise has spawned some truly memorable games. Warcraft 3: The Frozen Throne had a devoted eSports following for years, while World of Warcraft is the world's most successful MMORPG over ten years after its initial release. More recently, the Warcraft universe has taken a break from demon invasions and grisly political feuds to sit down, relax, and play a round or two of cards.

Hearthstone: Heroes of Warcraft, Blizzard's wildly popular digital card game, has been the smash hit no one saw coming before its beta period made it known worldwide. That kind of success comes with a lot of perks, and a pretty impressive cash flow is one of them.

According to a report published by online research firm SuperData, Hearthstone makes $20 million in revenue from just one month. Hearthstone has only been around for a little over a year, and is now well ahead of its competition, like Magic the Gathering's latest digital offering, Magic Duels: Origins. The card game based around popular characters in Warcraft lore is even ahead of Valve's Dota 2, which took in $18 million at last count in March. Given the scale of Dota 2's The International 5 last weekend, where a team won $6.2 million in the grand finals, Hearthstone's success is all the more impressive, although no digital game is close to eclipsing revenue king League of Legends' $123 million a month.

The most interesting thing about Hearthstone's financial success is that the game is free-to-play. Players can sign up through the Battle.net client and are given a tutorial, free cards to begin the game with, and multiple incentives that earn them gold to buy packs of new cards with later. However, Blizzard also offers card packs for money, as well as other game mechanics like the arena, where players draft decks and battle others who have done the same, and "adventures" that play out like well-loved raids in World of Warcraft. Hearthstone also offers cosmetic changes like different player portraits for cash, letting players customize the appearance of their favorite classes.

These kinds of micro-transactions really begin to add up for Blizzard, as SuperData estimates that Hearthstone currently enjoys 8 million PC players and 9 million players on mobile. Hearthstone is currently available for iPads, iPhones, and Android devices, and portability is definitely part of its appeal. A typical game of Hearthstone takes between 5 and 10 minutes, making it easy to play a quick game or two while on the go. The game's popularity has prompted Blizzard to release one expansion already, while the newest, The Grand Tournament, is coming out sometime this August.

Blizzard's success in the digital card market has caught everyone by surprise. The mixture of gameplay and presentation are unique to the genre, and Blizzard's professionalism is likely a large reason for Hearthstone's burgeoning player base and tournament scene. Time will tell if this kind of growth is sustainable, but for now, Blizzard's got another massive hit on their hands.

Hearthstone: Heroes of Warcraft is currently available for PC, Mac, iPad, iPhone, and Android devices.

Source: Venture Beat