# Key concepts

Legion is 1-vs-1 online game, played in a 2D top-down arena. You control several characters on the battlefield against the characters of the opponent. To win, kill all of your opponent's characters before they kill yours!

All games are 1 vs 1, meaning one player (you) versus another single player (one of your friend or any other player). However, each player can have from 3 to 6 characters on the battlefield, so one game can see a team of 6 characters vs 4, or 3 vs 3, or any combination of numbers. 

**Player:** the human behind the keyboard or phone.

**Character:** a playable unit that you can recruit, train, and use in the arena. Each player can have from 3 to 6 characters.

**Team:** the set of characters a player can deploy in a game.

Each character has a certain amount of Hit Points ([HP](https://guide.play-legion.io/core-mechanics#hp-mp-and-stats)). To win, you must kill all the characters of the opponent's team, by reducing the HP of all their characters to 0. This can be done by inflicting damage in various ways: direct attacks, [spells](https://guide.play-legion.io/items-and-spells#spells), setting the [terrain](https://guide.play-legion.io/gameplay/terrain-effects) on fire, etc. 

To prevent your opponent from winning, you must conversely preserve your character's HP, by healing them, resurrecting them, increasing their defense, or killing the enemy faster!