To have two commanders, both must have the partner ability (featured in the Magic: The Gathering—Commander™ (2016 Edition) set) or corresponding "partner with" abilities as the game begins. A creature with a "partner with" ability can't partner with any creature other than its designated partner. Losing a partner ability during the game doesn't cause either to cease to be your commander.
Pir, Imaginative Rascal
Once the game begins, your two commanders are tracked separately. If you cast one, you won't have to pay an additional {2} the first time you cast the other. A player loses the game after having been dealt 21 damage from one of them, not from both of them combined. Command Beacon's effect puts one into your hand from the command zone, not both.
An effect that checks whether you control your commander is satisfied if you control one or both of your two commanders.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Zoltan Boros
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
