Defense of the Ancients (DotA) started as a Warcraft III custom map by modder Eul, was refined by Steve 'Guinsoo' Feak, and then perfected by IceFrog into DotA Allstars, the version that took over the world. The concept was deceptively simple: two teams of five heroes defend their base while trying to destroy the enemy's Ancient. But the depth of hero interactions, item builds, and team strategies created complexity that rivaled chess. DotA was the most-played Warcraft III custom game by a massive margin, with millions of players in Southeast Asia, China, and Eastern Europe building grassroots competitive scenes long before formal esports infrastructure existed.