Commander damage

A player who has taken 21 or more combat damage from the same commander over the course of a game loses.

The rule

Commander damage is a second way to lose in Commander, next to life and poison. It counts combat damage only: damage a commander deals in combat to a player, added up over the whole game (CR 903.10a). Once a player has taken 21 or more from one commander, the state-based action makes them lose the game (CR 704.6c).

The count is kept per commander, not per opponent in total. 15 from one commander and 15 from another do not add up. With partners, each of the two commanders is counted on its own (CR 702.124d).

Damage that is not combat damage never counts, even if the commander itself deals it. Life loss from the same hit still lowers the life total as usual.

Brawl does not use this rule (CR 903.12h).

In Life Counter

Every commander is a coin in its owner's colour. Drag it onto the player it hit and the damage goes on that player's tally for that commander. The coin turns amber from 15, and at 21 the app marks the player as dead and says why.

A breakdown shows every source on one player, partners included. Undo takes back a wrong drag.