Commander (designation)

The commander (formerly general) is a designation to describe the central card of a Commander deck. It starts the game in, and is usually played from, the command zone. Being a commander is not a characteristic but a property of the card. 
==Description==
A player's choice of commander determines which other cards can be played in the deck by determining that deck's color identity. Players choose a legendary creature to be their commander. However, several abilities have the potential to expand the options for what may be chosen as a commander. Some legendary non-creature cards (usually planeswalkers) have an ability allowing them to be chosen as a commander. Players may choose a pair of valid commanders if each has the partner ability (including matching "partner with" pairings) or any of its variations, including friends forever and choose a background. In Brawl, any planeswalker can be designated as a commander even if it lacks the aforementioned ability allowing it to be one. The Mystery Booster test card <c>You're in Command</c> enables a player to change any of their creatures into their Commander (even if it is non-Legendary).
The commander's color identity restricts what cards may appear in the deck. If a player chooses to have two commanders, the color identity is the combined color identity of each.
While a commander is in the command zone, it may be cast. As an additional cost to cast a commander from the command zone, the player casting it must pay for each time that player has previously cast it from the command zone. This is called the commander tax. If a player chooses to have two commanders, each is counted separately. If a commander is put into its owner's graveyard, is exiled, or is returned to a player's hand or library from anywhere, that player may choose to put it into the command zone as a state-based action.
If a player has been dealt 21 points of combat damage by a particular commander during a game, that player loses the game. If a player chooses to have two commanders, each is counted separately.
==Rules==
===Commander tax===
==Commander interaction cards==
Some cards specifically interact with your commander. If a player has two commanders, then each is counted separately, except for abilities referring to their color identity, in which case the color identity of the commander is the combined color identity of each of that player's commanders.
===Commander Storm===
Cards with the commander storm mechanic, introduced in Commander 2018, can copy itself for each time the commander was cast from the command zone.
===Lieutenant===
Cards with the lieutenant ability word, introduced in Commander 2014, have an effect if your commander is on the battlefield.
===Choose a Background===
Background cards, introduced in Commander Legends: Battle for Baldur's Gate, affect your commanders.
===Commander creatures===
Some cards, usually Backgrounds themselves, refer to "Commander creatures." Those don't refer to a Background enchantment that is a Commander unless it is also a creature.
If a card refers to your Commander, it means either the legendary creature or the legendary Background enchantment. So cards like <c>Command Beacon</c> can fetch either the legendary creature or the legendary Background. Anything that cares about whether you control your Commander will be satisfied if you control one or both of them. Cards like <c>Command Tower</c> can add mana of either of your commander's color identities.
==References==