League of Legends (LoL) is a five-player online battle arena video game based on the Warcraft III: The Frozen Throne mod Defense of the Ancients. Designed by developer Riot Games, LoL was unofficially released in October 2009. The game is a free-to-play title supported by microtransactions. LoL is one of the most popular Internet games. According to Riot Games, it is played by 650 million people.
In LoL, players assume the role of an unseen "summoner" that controls a "champion" with unique abilities and battle against a team of other players or computer-controlled champions. The goal is usually to destroy the opposing team's "nexus", a structure that lies at the heart of a base protected by defensive structures, although other distinct game modes exist as well. Each League of Legends match is discrete, with all champions starting off fairly weak but increasing in strength by accumulating items and experience over the course of the game.