Defense of the Ancients (DotA) is a multiplayer online battle arena mod for the video game Warcraft III: Reign of Chaos and its expansion, Warcraft III: The Frozen Throne, based on the "Aeon of Strife" map for StarCraft. The scenario objective is for each team to destroy the opponents' Ancient, heavily guarded structures at opposing corners of the map. Players use powerful units known as heroes, and are assisted by allied heroes and AI-controlled fighters.