The objective of the scenario is for each team to destroy the opponents' Ancients, 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. As in role-playing games, players level up their heroes and use gold to buy items during the mission.
The scenario was developed with the "World Editor" of Reign of Chaos, and was updated upon the release of its expansion, The Frozen Throne.
There have been many variations of the original concept; the most popular being DotA Allstars, which eventually was simplified to DotA with the release of version 6.68. This specific scenario has been maintained by several authors during development, the latest of whom being the anonymous developer known as "IceFrog" developing the game since 2005.
Since its original release, DotA has become a feature at several worldwide tournaments, including Blizzard Entertainment's BlizzCon and the Asian World Cyber Games, as well as the Cyberathlete Amateur and CyberEvolution leagues; in a 2008 article of video game industry website Gamasutra, the article's author claimed that "DotA is likely the most popular and most-discussed free, non-supported game mod in the world". Valve Corporation is currently developing a stand-alone sequel, DotA 2
DotA pits two teams of players against each other: the Sentinel and the Scourge. Players on the Sentinel team are based at the southwest corner of the map, and those on the Scourge team are based at the northeast corner. Each base is defended by towers and waves of units which guard the main paths leading to their base. In the center of each base is the "Ancient", a building that must be destroyed to win the game.
Each human player controls one hero, a powerful unit with unique abilities. In DotA, players on each side choose one of 110 heroes, heroes are updating and increasing. Each with different abilities and tactical advantages over other heroes. The scenario is highly team-oriented; it is difficult for one player to carry the team to victory alone. Defense of the Ancients allows up to ten players in a five-versus-five format and an additional two slots for referees or observers, often with an equal number of players on each side.
The differences between The Sentinel base (top) and the Scourge base (bottom)
Because the gameplay revolves around strengthening individual heroes, it does not require one to focus on resource management and base-building, unlike most traditional real-time strategy games. Killing computer-controlled or neutral units earns the player experience points; when enough experience is accumulated, the player gains a level. Leveling up improves the hero's toughness and the damage they can inflict, and allows players to upgrade their spells or skills.
In addition to accumulating experience, players also manage a single resource: gold. The typical resource-gathering of Warcraft III is replaced by a combat-oriented money system; in addition to a small periodic income, heroes earn gold by killing hostile units, base structures, and enemy heroes. This has caused emphasis on a technique called "last-hitting," which is when the player attacks a hostile unit when "its hit points are low enough to kill it with one blow".
Using gold, players buy items to strengthen their hero and gain abilities; certain items can be combined with recipes to create more powerful items. Buying items that suit one's hero is an important tactical element of the mod. Item choice also affects play style, as any given item may increase one statistic while leaving another unchanged.
Warcraft III is the third title in the Warcraft series of real-time strategy games developed by Blizzard Entertainment.
The first version of Defense of the Ancients was released in 2003 by a mapmaker under the alias of Eul who based the map on a previous StarCraft scenario known as "Aeon of Strife". After the release of Warcraft's expansion The Frozen Throne, which added new features to the World Editor, Eul did not update the scenario. Other mapmakers produced spinoffs that added new heroes, items, and features.
Among the DotA variants created in the wake of Eul's map, there was DotA Allstars, developed by modder Steve Feak (under the alias Guinsoo); this version would become today's dominant version of the map, simply known as Defense of the Ancients. Feak said when he began developing DotA Allstars, he had no idea how popular the game would eventually become; the emerging success of the gametype inspired him to design a new title around what he considered an emerging game genre. Feak added a recipe system for items so that player's equipment would scale as they grew more powerful, as well as a powerful boss character called Roshan (named after his bowling ball) who required an entire team to defeat.
Feak used a battle.net chat channel as a place for DotA players to congregate,but DotA Allstars had no official site for discussions and hosting. Subsequently, the leaders of the DotA Allstars clan, TDA, proposed that a dedicated web site be created to replace the various online alternatives that were infrequently updated or improperly maintained. TDA member Steve "Pendragon" Mescon created the former official community site, dota-allstars.com, on October 14, 2004.
Towards the end of his association with the map, Feak primarily worked on optimizing the map before handing over control to another developer after version 6.01. The new author, IceFrog, added new features, heroes, and fixes. Each release is accompanied by a changelog. IceFrog was at one time highly reclusive, refusing to give interviews; the only evidence of his authorship was the map maker's email account on the official website and the name branded on the game's loading screen.
Defense of the Ancients is maintained via official forums. Users can post ideas for new heroes or items, some of which are added to the map. Players have contributed icons and hero descriptions and created the artwork displayed while the map loads, and suggestions for changes to existing heroes or items are taken seriously; IceFrog once changed a new hero less than two weeks after the new version of the map was released. Versions of the scenario where enemy heroes are controlled by artificial intelligences have also been released. Mescon continued to maintain dota-allstars.com, which by the end of IceFrog's affiliation in May 2009 had over 1,500,000 registered users and had received over one million unique visitors every month.
Due to their separation, IceFrog announced that he would be further developing a new official site, playdota.com, while continuing game development; Mescon closed dota-allstars on July 22, 2010, citing dropping statistics and his new passion for League of Legends as the reason for its end.