The Companion rule, the 2020 errata, and why Lurrus is gone but Yorion isn't

TL;DR: Companion was printed in Ikoria (April 2020) with no cost to put it into your hand. Two months later Wizards added a 3-mana tax because the mechanic broke every format. Lurrus of the Dream-Den is banned in EDH because a 2-mana permanent-CMC restriction is trivial to satisfy. Yorion, Sky Nomad isn't banned because its deck-size restriction (20+ cards more than minimum) is literally impossible to satisfy in Commander unless you run Yorion as your commander — and then it's just a 5-mana blink effect with no unfair advantage.

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How Companion worked when it shipped

Ikoria released April 24, 2020. Ten legendary creatures had a new keyword: Companion. The mechanic worked like this (original rules text):

"If this card is your chosen companion, you may cast it once from outside the game."

The deckbuilding restriction appeared on the card. If you satisfied the restriction during deck construction, you declared the card as your companion before the game started. You got an eighth card that started outside your hand and outside your library. Once per game you could cast it from that external zone for its normal mana cost.

No tax. No additional cost. Just build the deck to satisfy the restriction and you started every game with an extra card.

This was a mistake.

The June 2020 errata (CR 702.139)

On June 1, 2020 — five weeks after Ikoria release — Wizards announced an emergency rules change. Companion got errata'd. The new rule (CR 702.139b):

"Before the beginning of your first main phase, you may pay {3} to put your companion from outside the game into your hand."

You still got the eighth card. You still got the guarantee. But now it cost three generic mana to move that card from the external zone into your hand. You could pay the cost during your first main phase on any turn (yours or an opponent's), but you had to pay.

This was the first functional errata Wizards had issued in over a decade. The mechanic was so format-warping that they changed how printed cards worked rather than ban everything.

Lurrus of the Dream-Den

Why Lurrus broke everything

Lurrus of the Dream-Den's companion restriction:

"Each permanent card in your starting deck has mana value 2 or less."

Lurrus lets you cast a permanent spell with mana value 2 or less from your graveyard each turn. In Vintage, Legacy, and Modern that's absurdly strong. Mishra's Bauble, Mox Opal, Lurrus herself — the restriction costs nothing in those formats because the best cards are cheap.

Even after the 3-mana tax was added, Lurrus was too good. She was banned in Vintage (May 2020), banned in Legacy (March 2022), and banned in Pioneer (August 2022). The only 60-card constructed format where she's still legal is Modern, and she still sees play.

In Commander the math is worse. A 2-CMC ceiling sounds restrictive until you look at the staples. Sol Ring, Arcane Signet, Sensei's Divining Top, Lightning Greaves, Rhystic Study, Bloom Tender, Dockside Extortionist (when it was legal), Esper Sentinel, all the talismans, all the signets. You can build a tier-1 deck that satisfies Lurrus's restriction and loses almost nothing.

The EDH Rules Committee banned Lurrus on April 20, 2020 — four days before Ikoria even released. The ban announcement cited the restriction being "trivially easy to satisfy" and the companion mechanic giving "an outsized advantage in a singleton format."

Lurrus never had a legal day in Commander.

Why Yorion didn't get banned

Yorion, Sky Nomad

Yorion, Sky Nomad's companion restriction:

"Your starting deck contains at least twenty cards more than the minimum deck size."

In Standard (60-card minimum) you play 80 cards. In Modern you play 80 cards. In Pioneer you play 80 cards. You dilute your deck's consistency to get a guaranteed 5-mana blink effect. The trade-off is real.

In Commander the minimum deck size is 100 cards. Twenty more than minimum is 120 cards.

But Commander is a singleton format. Your deck IS your commander plus 99 other cards. If you run Yorion as your commander, your deck is 100 cards (Yorion in the command zone + 99 in the library). You don't get to declare Yorion as a companion because your deck is exactly the minimum, not 20 cards over.

If you try to run a 120-card deck with a different commander and Yorion in the 99, Yorion's companion ability doesn't work. The companion rule requires the companion card to start outside the game (CR 702.139a). Cards in your library are not outside the game. You'd have to exile Yorion before the game starts, which violates the commander-deck construction rules.

The only way to use Yorion as a companion in EDH is to make Yorion your commander. At that point the companion mechanic does nothing. Yorion is just in the command zone like every other commander. The 3-mana tax doesn't apply. The deckbuilding restriction is automatically satisfied. You're playing a 5-mana blink commander with no special advantage.

Yorion sees play in Commander. Yorion is not banned. The mechanic's design accidentally made it fair in a 100-card singleton format.

The Lutri problem (and why one companion IS banned for mechanical reasons)

Lutri, the Spellchaser

Lutri, the Spellchaser's companion restriction:

"Each nonland card in your starting deck has a different name."

Commander is already singleton. Lutri's restriction is automatically satisfied in every legal EDH deck. If Lutri were legal as a companion, every Izzet deck would run Lutri as a free eighth card. No cost, no trade-off, just a guaranteed 3-mana instant-speed Fork effect in every game.

Lutri was also banned on April 20, 2020, same day as Lurrus. The ban announcement said:

"Its companion mechanic would grant all Izzet decks a powerful extra card with no deckbuilding cost."

Lutri's ban is about the companion mechanic itself, not the card's power level. If you put Lutri in the 99 or in the command zone (not as a companion), it's a fine card. Instant-speed Fork is good but not broken. The problem is the free eighth-card that every Izzet player would automatically get.

What this means for deck construction

You cannot use companions in Commander the way you can in other formats. The mechanic assumes a minimum deck size that can be increased. Commander's structure breaks that assumption.

The three possible cases:

1. Companion restriction is trivially satisfied (Lurrus, Lutri): Banned because the advantage is free.

2. Companion restriction is impossible to satisfy (Yorion, and most of the others): You can only meet the restriction by making the companion your commander, which makes the companion ability meaningless.

3. Companion restriction requires real deckbuilding cost: Still usually impossible because of the singleton rule or the 100-card fixed size.

Kaheera (only Cats, Elementals, Nightmares, Dinosaurs, and Beasts) works as a commander for tribal decks. Gyruda (all nonland cards have even mana value) is possible but painful in a format where Sol Ring and the best card draw are odd-CMC. Zirda (deck contains only permanents with activated abilities) is possible but restrictive enough that it's not worth running.

The companion mechanic was designed for 60-card formats where you can modify deck size and play four copies of each card. Commander's singleton 100-card structure makes the mechanic either broken (free advantage) or inert (no advantage). Lurrus and Lutri got banned. Yorion stayed legal because it doesn't do anything special.

The ruling that matters (CR 702.139)

If you're ever in a pod where someone claims they're running a companion, check this:

CR 702.139a: "Before the game begins, you may reveal one card you own from outside the game with a companion ability whose condition is fulfilled by your starting deck."

In Commander, "outside the game" means your sideboard (which doesn't exist in EDH) or the command zone. If the companion is your commander, it's in the command zone but the companion ability doesn't do anything a normal commander doesn't do. If the companion is in your library (the 99), it's not outside the game and the ability doesn't work.

The 3-mana tax (CR 702.139b) only applies if you legally declared the companion before the game started. No legal declaration means no companion ability means no tax to pay.

If someone tries to put Yorion in their 99 and then claim companion status mid-game, that's not how the rule works. Yorion is just a creature card in their library. They draw it or tutor it like any other card.

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The Ikoria companion mechanic shipped broken, got emergency errata'd five weeks later, and still caused bans across multiple formats. In Commander it's mostly a non-issue because the format's structure makes most companions impossible to use and the obviously broken ones got banned immediately. Lurrus is gone. Yorion is here and fair. The rule works the way it's supposed to — it just took Wizards two tries to get it there.

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