Who developed Dota 2?

@matilda 

Dota 2 is a multiplayer online battle arena (MOBA) video game developed and published by Valve Corporation. It was released in 2013 as a sequel to Defense of the Ancients (DotA), which was a community-created mod for Blizzard Entertainment's Warcraft III: Reign of Chaos. The development of Dota 2 was led by IceFrog, who was also the lead designer of the original DotA.