Wall of All

Partner (You can have two commanders if both
have partner.)
If Wall of All is your only commander, before the start
of the game, you may choose a legendary creature from
your library and give it partner, that creature becomes
a commander for the rest of the game and is moved to
the command zone with Wall of All.

Wall of All must be in play before casting your second
commander, and gets +1/+1 and costs {2} less for every
time one of your commanders has died this game.
{t}, Pay {5}: