Dota is a series of strategy video games. The series began in 2003 with the release of Defense of the Ancients (DotA), a fan-developed multiplayer online battle arena (MOBA) mod for the video game Warcraft III: Reign of Chaos and its expansion, The Frozen Throne. The original mod features gameplay centered around two teams of up to five players who assume control of individual characters called "heroes", which must coordinate to destroy the enemy's central base structure called an "Ancient", to win the game. Ownership and development of DotA were passed on multiple times since its initial release until Valve hired the mod's lead designer IceFrog and after an ongoing legal dispute with Blizzard Entertainment, the developer of Warcraft III, brokered a deal that allowed for Valve to inherit the trademark to the Dota name.