Blizzard Entertainment has developed 19 games since 1991, the majority of which are in the Warcraft, Diablo, and StarCraft series. Since the release of Warcraft: Orcs & Humans (1994), Diablo (1997), and StarCraft (1998), the focus has been almost exclusively on those three franchises, with the Overwatch (2016) as sole exception. Additionally, Blizzard has released two spin-offs to the main franchises: Hearthstone (2014), and Heroes of the Storm (2015).