Dota is the deepest multi-player action RTS game ever made and there's always a new strategy or tactic to discover. It's completely free to play and always .

Dota 2 is a 2013 multiplayer online battle arena (MOBA) video game by Valve. The game is a sequel to Defense of the Ancients (DotA), a community-created mod for Blizzard Entertainment's Warcraft III: Reign of Chaos.