Hearthstone: Heroes of Warcraft is a free-to-play online collectible card video game developed and published by Blizzard Entertainment, released worldwide on March 11, 2014. Hearthstone builds upon the lore of the Warcraft series, using characters, creatures, and relics from the series. Initially released forMicrosoft Windows and OS X personal computers, Hearthstone also supportsiOS and Android devices, and features cross-platform play, allowing users on any device to compete with each other, restricted only by geographical region account limits.