Hearthstone (formerly known as Hearthstone: ‘Heroes of Warcraft’) is an online collectible card game created by Blizzard Entertainment. It is focused on the universe of Warcraft, and is free to download, although with optional purchases to accelerate the pace of card collection and access to extra content.
The game was announced on March 22, 2013, however, a demo was presented during PAX East 2013. It was officially released on March 11, 2014. It is currently available for Windows, OS X and iOS and Android mobile devices. In addition to the initial card collection (Basic and Classical), Hearthstone regularly introduces expansions (Goblins vs. Gnomes, The Grand Tournament, Whispers of the Ancient Gods, Gadgetzan Mafias, Journey to Un’Goro, Knights of the Frozen Throne, Kobolds & Catacombs, The Haunted Forest, The Armagebum Project, The Rastakhan Arena and the most recent: The Rise of Shadows) and adventures (The Curse of Naxxramas, Blackrock Mountain, The Expeditionary League and A Night in Kharazan) with New cards and mechanics.