League of Legends is a 3D, third-person multiplayer online battle arena (MOBA) game. In League of Legends, human or AI-controlled players each control a character, called a champion, and form two opposing teams. In the most popular "classic" mode, each team begins with a central building, called a nexus, protected by defensive structures. The object of each game is to breach the opposing team's base and destroy their nexus. Each nexus will also occasionally spawn weak, autonomous attackers called "minions" that travel along paths called "lanes" toward the enemy base. Between the lanes lies an area called the "jungle", where neutral monsters reside that can be killed by both teams.
Players begin each game with little power and health, as a champion's experience points, gold and items are not preserved between games. Instead, players must gain gold and experience through performing various actions in each game. Though players receive a small amount of gold income passively, both experience and larger quantities of gold are generally only attained through combat, such as by killing other champions, destroying defensive turrets and dealing the final blow to enemy minions. Gold can be used to purchase items, which will provide beneficial effects for a champion, such as being able to deal or absorb more damage and thus be more likely to kill their opponents in combat. A champion will respawn at their base not long after their death, with the delay increasing as the game progresses.
Each champion has distinct abilities with a variety of effects. These effects vary greatly from champion to champion, and include dealing damage, providing buffs to allies and inflicting debuffs to enemies. In addition to the standard abilities, each champion also has a passive ability, which provide various beneficial effects. Furthermore, before each game, each player can select two additional abilities, called "summoner spells", that can be used with any champion.
Other maps include the Twisted Treeline (consisting of two lanes) and the Howling Abyss (consisting of a single lane with no jungle). The other distinct game mode is known as Dominion, in which players are unable to directly attack the opposing nexus; they are only able to damage it indirectly by killing opponents, and capturing and holding the five towers around the map.
All game modes use automated matchmaking based on the Elo formula, with proprietary adjustments.