If you control two Commanders in a Partner game, does damage from each count separately toward commander damage?

In the Commander format, a player loses the game if they have been dealt 21 or more combat damage by a single commander over the course of the game (Commander rule, supported by CR 903.10a). The key word is single: each commander has its own independent damage counter tracked per opponent.

When two commanders are paired via the Partner mechanic (CR 702.124), each partner is still its own individual commander. Damage dealt by Commander A and damage dealt by Commander B to the same opponent are tracked in two completely separate pools. There is no combining or adding of the two totals together to reach the 21-damage threshold.

This means an opponent must receive 21 or more combat damage specifically from Commander A or 21 or more combat damage specifically from Commander B to lose via commander damage — not 11 from one plus 10 from the other.

Concrete example: You control Rograkh, Son of Rohgahh and Ardenn, Intrepid Archaeologist as partners. Over several turns, Rograkh deals 13 combat damage to an opponent, and Ardenn deals 10 combat damage to that same opponent. The opponent has taken 23 total combat damage from your commanders, but neither commander has individually hit 21 — so the opponent does not lose to commander damage from either one.

This separation is intentional by design and is consistent with CR 903.10a, which specifies damage is tracked per commander, and CR 702.124a, which confirms each partner is a separate commander in the command zone.