“Choose a Background” means “You may designate two cards as your commander rather than one if one of them is this card and the other is a legendary Background enchantment card.” You can’t designate two cards as your commander if one has a “choose a Background” ability and the other is not a legendary Background enchantment card, and legendary Background enchantment cards can’t be your commander unless you have also designated a commander with “choose a Background.”
November 14, 2025 · Avatar: The Last Airbender
“Friends forever” means “You may designate two legendary creature cards as your commander rather than one if each of them has friends forever.”
October 13, 2023 · Doctor Who
“Choose a Background” means “You may designate two cards as your commander rather than one if one of them is this card and the other is a legendary Background enchantment card.” You can’t designate two cards as your commander if one has a “choose a Background” ability and the other is not a legendary Background enchantment card, and legendary Background enchantment cards can’t be your commander unless you have also designated a commander with “choose a Background.”