Gale, Waterdeep Prodigy

Both commanders start in the command zone, and the remaining 98 cards (or 58 cards in a Commander Draft game) of your deck are shuffled to become your library.

If something refers to your commander while you have two commanders, it refers to one of them of your choice. If you are instructed to perform an action on your commander (e.g. put it from the command zone into your hand due to Command Beacon), you choose one of your commanders at the time the effect happens.

If a card refers to a commander creature you own, a Background won't usually be counted or included for that effect. If another spell or ability causes your Background to become a creature, however, it will be included. Any effect that refers to your commander or a commander you own or control without specifying creature will apply to a Background that is your commander, as appropriate.

If your commander loses the choose a Background ability or stops being a Background during the game, as appropriate, it is still your commander.

If you control a Background that grants an ability to commander creatures you own, and you own more than one commander creature, each of them will have that ability.

Choose a Background is a variant of the partner ability. You may have two commanders if one of them is a legendary creature with the choose a background ability and the other is a legendary Background enchantment. Backgrounds and cards with choose a Background do not interact with cards which have any other partner ability.