Multiplayer online battle arena

Multiplayer online battle arena is a subgenre of strategy video games in which each player controls a single character as part of a team competing against another team of players, usually on a map in an isometric perspective. The ultimate objective is to destroy the opposing team's main structure with the assistance of periodically-spawned computer-controlled units that march forward along set paths; however, MOBA games can have other victory conditions, such as defeating every player on the enemy team. Player characters typically have a set of unique abilities that improve over the course of a game and which contribute to the team's overall strategy. This type of multiplayer online video games originated as a subgenre of real-time strategy, though MOBA players usually do not construct buildings or units. Moreover, there are examples of MOBA games that cannot be considered RTS at all, such as Smite, and Paragon. The genre is seen as a fusion of real-time strategy, role-playing, and action games.
The first widely accepted "game" in the genre was Aeon of Strife, a fan-made custom map for StarCraft in which four players each control a single powerful unit and, aided by weak computer-controlled units, compete against a stronger computer. Defense of the Ancients, a community-created mod from 2003, that includes a map based on AoS for ' and ', was one of the first major titles of its genre and the first MOBA for which sponsored tournaments have been held. It was followed by two spiritual successors, League of Legends and Heroes of Newerth, and eventually a standalone sequel, simply titled Dota 2, as well as numerous other games in the genre, such as Heroes of the Storm.
By the early 2010s, the genre has become a big part of the esports category. In 2018 alone, the prize pools reached over 60 million dollars, which is about 40% of the total esports prize pools in the same year. Major esports professional tournaments are held in venues that can hold tens of thousands of spectators and are streamed online to millions more. A strong fanbase has opened up the opportunity for sponsorship and advertising, eventually leading the genre to become a global cultural phenomenon.


Each match starts with two opposing teams, typically made up of five players. Players work together as a team to achieve the ultimate victory condition which is to destroy their enemy's base though some games have the option of different victory conditions. Usually, each team has main structure which must be protected until opposing team's is destroyed, preventing enemy team from doing the same. The first team to destroy the opposing team's main structure wins the match. Destroying other structures within the opposing team's base may confer other benefits. Defensive structures, which are usually automatic "towers", are in place to prevent this, as well as relatively weak computer-controlled units, called "minions", which periodically spawn in groups at the base and marching down predefined paths toward the enemy base. There are typically 3 "lanes" that are the main ways of getting from one base to another; in between the lanes is an uncharted area called the "jungle." The lanes are known as top, middle and bottom lane, or, in gamer shorthand – "top", "mid" and "bot".
A player controls a single powerful in-game unit, called "hero" or "champion", who comes with a diverse set of unique abilities. When a hero stands near a killed enemy unit or kills an enemy unit, they gain experience points and gold which allow the hero to level up and buy items at a store. When a hero levels up, they may strengthen one of their abilities which they typically have four of. If a hero runs out of health points and dies, he is removed from active play until a respawn timer counts down to zero, where he is then respawned in his base. Respawn time generally increases as hero levels up.
Heroes typically fall into one of several roles, such as tank, damage dealer, healer, and support, each of which having a unique design, strengths, and weaknesses. Also typically, MOBA games offer a large number of viable playable heroes for the player to choose from – League of Legends, for instance, began with 40, and has added at least one new one every month for its entire lifespan, reaching 100 in 2012. This adds to the learning curve of the game as players learn the game's goals and strategies. Choosing a character who complements player's teammates and counters his opponents, opens up a strategy before the beginning of the match itself. Players usually find at least one hero they excel at playing, and familiarize themselves with the remaining roster. Additionally, each hero is deliberately limited in the roles they can fulfill. No one hero is ever powerful enough to win the game without support from their team. This creates a strong emphasis on teamwork and cooperation.
Each player typically receives a small amount of gold per second during the course of the game. Moderate amounts of gold are rewarded for killing hostile computer-controlled units and larger amounts are rewarded for killing enemy heroes. Gold is used by heroes to buy a variety of different items that range in price and impact. For the most part, this involves improving the combat viability of the hero, although there may be other items that support the hero or team as a whole in different ways.
As the heroes of each team get stronger, they can use multiple strategies to gain an advantage. These strategies can include securing objectives, killing enemy heroes and farming gold by killing computer-controlled units. The stronger a team gets, the more capable they are at destroying the enemy team and their base.

Character classes and roles

In most MOBAs, playable characters have assigned classes such as "tank", "marksman", "mage", "fighter", "assassin", "support" and "healer". During the match, they can be played as "carry", "support" and "ganker"; however the number and type of roles can differ depending on the game. The carry role is expected to scale and itemize themselves to do the most damage against enemy characters and objectives, but may also require protection and assistance from their team members. Supports are characters who support the entire team with abilities that are meant to aid allies and disable or slightly harm enemies. Some supports have healing abilities which can be vital factor in your team composition’s success, giving health and sustain to an ally while limiting enemy's options in terms of play patterns. Ganker roles are flexible, as they have both carry and support skills that are used to disrupt and eliminate enemies, thus giving their teammates an advantage over their opponents. Gankers can "act as a strategist, decision-maker or supporter depending on the team's needs." Player roles can also be classified by the particular lane they are focusing on, such as "top laner", "mid laner", and "bottom laner", or by their role in a teamfight, such as "frontliner", "damage dealer", "healer", "flex", and the "offlaner".

Resemblance to other genres

As a fusion of real-time strategy, role-playing, and action games, members of the genre have lost many traditional RTS elements. This type of games moved away from constructing additional structures, base management, army building, and controlling additional units. Map and the main structures for each team are still present, and destroying enemy main structure will secure victory as the ultimate victory condition. Players can find various friendly and enemy units on the map at any given time assisting each team, however these units are computer-controlled and players usually don't have direct control over their movement and creation; instead, they march forward along set paths. Unlike in real-time strategy games, player has control over the only one single unit, called hero or champion. However, some MOBA games have certain heroes which control a few specialized units, but not on a massive scale which is typical for RTS.
The MOBA genre resembles role-playing games in gameplay, though the MOBA genre focuses on the multiplayer battle in the arena-like environment, while RPG as genre typically revolve around single player story and its chapters, and exploration of different locations. A key features, such as control over one character in a party, growth in power over the course of match, learning new thematic abilities, using of mana, leveling and accumulation of experience points, equipment and inventory management, completing quests, and fighting with the stationary boss monsters, have resemblance with role-playing games.



The roots of the genre can be traced back decades to one of the earliest real-time strategy titles, the 1989 Sega Mega Drive/Genesis game Herzog Zwei. It has been cited as a precursor to, or an early example of, the MOBA genre. It used a similar formula, where each player controls a single command unit in one of two opposing sides on a battlefield. Herzog Zweis influence is also apparent in several later MOBA games such as ' and AirMech.
In 1998,
' featured a strategic Precinct Assault mode similar to Herzog Zwei, in which the players could actively fight alongside generated non-player units. The PC version also allowed for online competitive play, technically making Future Cop: LAPD the first MOBA game ever released as, unlike Herzog Zwei, it meets the criteria of an online battle arena.
Also in 1998, computer game company Blizzard Entertainment released its best-selling real-time strategy game StarCraft with a suite of game editing tools called StarEdit. The tools allowed members of the public to design and create custom maps that allowed play that was different from the normal maps. A modder known as Aeon64 made a custom map named Aeon of Strife that became popular. Aeon64 stated that he was attempting to create gameplay similar to that of Future Cop: LAPD's Precinct Assault mode. In the Aeon of Strife map, players controlled a single powerful hero unit fighting amidst three lanes, though terrain outside these lanes was nearly vacant.

Establishing the genre: 2000s

In 2002, Blizzard released ', with the accompanying Warcraft III World Editor. Both the multiplayer online battle arena and tower defense subgenres took substantive shape within the WC3 modding community. A modder named Eul began converting Aeon of Strife into the Warcraft III engine, calling the map Defense of the Ancients '. Eul substantially improved the complexity of play from the original Aeon of Strife mod. Shortly after creating the custom DotA map, Eul left the modding scene. With no clear successor, Warcraft III modders created a variety of maps based on DotA and featuring different heroes. In 2003, after the release of, a map creator named Meian created a DotA variant closely modeled on Eul's map, but combining heroes from the many other versions of DotA that existed at the time. Called DotA: Allstars, it was inherited after a few months by a modder called Steve "Guinsoo" Feak, and under his guidance it became the dominant map of the genre. After more than a year of maintaining the DotA: Allstars map, with the impending release of an update that significantly changed the map layout, Guinsoo left the development to his adjutant Neichus in the year 2005. After some weeks of development and some versions released, the latter turned over responsibility to a modder named IceFrog, who initiated large changes to the mechanics that deepened its complexity and capacity for innovative gameplay. The changes conducted by IceFrog were well-received and the number of users on the Dota: Allstars forum is thought to have peaked at over one million. Defense of the Ancients is largely attributed to being the most significant inspiration for the multiplayer online battle arena video game genre in the years to come.

Mainstream popularity: 2008–present

By 2008, the popularity of DotA had attracted commercial attention. That year, The Casual Collective released Minions, a Flash web game.
Gas Powered Games also released the first stand-alone commercial title in the genre, Demigod. In late 2009, Riot Games' debut title, League of Legends initially designed by the one of the original creators of DotA Allstars, Steve Feak, was released.
Riot began to refer to the game's genre as a multiplayer online battle arena.
Also in 2009, IceFrog, who had continued to develop DotA: Allstars, was hired by Valve, in order to design a sequel to the original map.
In 2010, S2 Games released Heroes of Newerth, with a large portion of its gameplay and aesthetics based on DotA: Allstars. The same year, Valve announced Dota 2 and subsequently secured the franchise's intellectual property rights, after being contested by Riot Games for the DotA trademark. In 2012, Activision Blizzard settled a trademark dispute with Valve over the usage of the DOTA trademark and announced their own standalone game, which was eventually named Heroes of the Storm. Dota 2 was released in 2013, and was referred to by Valve as an "action real-time strategy" game. In 2014, Hi-Rez Studios released Smite, a MOBA with a third-person perspective. Heroes of the Storm was released in 2015, featuring numerous original heroes from Warcraft III and other Blizzard's franchises. Blizzard adopted their own personal dictation for their game's genre with "hero brawler", citing its focus on action.

Next-generation wave and market saturation

In recent years, numerous video game developers and publishers, following the success of League of Legends and Dota 2, tried to be part of the next-generation MOBA wave by putting their own twist in the genre, releasing games such as Battlerite, and AirMech. However, not everyone succeeded. After years of development, many games which were supported by "big-name" publishers have never been officially released or their servers were shut down shortly after release. The most notable examples are Dawngate by Electronic Arts, DC Comics-based Infinite Crisis by Warner Bros., Arena of Fate by Crytek, Gigantic by Perfect World Entertainment, Master X Master by NCSoft, and Paragon by Epic Games.
During the 2010s, with the expansion of the smartphone market, numerous MOBA titles have been released for portable devices, such as Vainglory, and Arena of Valor.


In the original DotA, each player controls only one powerful unit rather than a big army. While it still kept the large scale, core mechanics, and goals of the real-time strategy games, DotA attempted to avoid "clickfest" gameplay in which high actions per minute scores are mandatory for efficient playing, changing focus to the actual teamwork, coordination, and tactics. This made mod highly popular, as its dynamic and unpredictable fights, complex map, and hero-centric gameplay create a more competitive environment and opportunities for outplaying the enemy team. By the early 2010s, multiplayer online battle arena has become a prominent genre in esports tournaments. In 2018 alone, the prize pools reached over 60 million dollars, which is about 40% of the total esports prize pools in the same year. MOBAs are some of the most watched games in the world. Major esports professional tournaments are held in venues that can hold tens of thousands of spectators and are streamed online to millions more. A strong fanbase has opened up the opportunity for sponsorship and advertising, eventually leading the genre to become a global cultural phenomenon.
A free-to-play business model, which is used by the biggest MOBA titles, have contributed to the genre's overall popularity. Players are able to download and play AAA-quality games at no cost. These games are generating revenue by selling cosmetic elements, including skins, voice lines, customized “mounts”, and announcers, but none of these give the functional gameplay advantages to the buyer. As of 2012, free-to-play MOBAs, such as League of Legends, Dota 2, Heroes of the Storm, and Smite were among the most popular PC games. The success in the genre has helped convince many video game publishers to copy the free-to-play MOBA model. SuperData Research reported that the genre generated over $2.5 billion of revenue in 2017.
Similar to fighting games, MOBAs offer a large number of viable player characters for the player to choose from, each of which having different abilities, strengths, and weaknesses to make the game play style different. That means it's very likely that any player can find a hero who enables his specific multiplayer skills. Choosing a character who complements player's teammates and counters his opponents, opens up a strategy before the beginning of the match itself. Playable characters blend a variety of fantasy tropes, such as high fantasy, dark fantasy, science fiction, sword and sorcery, Lovecraftian horror, cyberpunk and steampunk, featuring numerous references to popular culture and mythology.

Data analytics and match prediction

Due to the large volume of MOBA matches played on a daily basis globally, MOBA has become a platform to apply big data tools to predict match outcomes based on in-game factors such as hero kill/death/assist ratios, gold earned, time of a match, synergy with other players, team composition, and other parameters. Artificial Intelligence playing in matches and predicting match outcomes is being researched. Open AI developed the Open AI Five which were first showcased at the Dota 2 World Championship, The International 2017, during a 1v1 demonstration. Open AI returned to The International 2018 where the Open AI Five played in two games against professional players.