Mystery Booster Commander Edition comes with a few changes to Magic's game rules, most of which are organizational in nature, and one Oracle update we've mentioned previously.

Comprehensive Rules Changes

This is a summary of the rules changes planned for Magic with the release of Mystery Booster Commander Edition. The official rules can be found on our rules page. If there should be a discrepancy between this summary and the official rules, the official rules take precedence.

New Rules

903.5e

This rule governs how rulebreaker abilities work. Specifically, it allows them to function at the appropriate time (before the game begins). Of course, this only works if the card with the rulebreaker ability in question is your commander.

Updated Rules

122.1g

Rule 704.5w was added in a previous update to handle a non-Siege battle with 0 defense counters (it gets put into its owner's graveyard thanks to a state-based action), but 122.1g was never updated to match. Until now, that is!

201.4f

This rule notes that when a player is instructed to choose the name of a card, they may choose the name of the Adventure on an adventurer card. The rules regarding cards with an Omen and cards with a prepared spell already stated that players could choose the names of those spells, but we updated this rule to include adventurer cards for clarity.

205.3j

This release added seven new planeswalker subtypes: Arzakon, Dyfed, Feroz, Greensleeves, Sifa, Thomil, and Worzel. (The mere mention of Arzakon brings me a great deal of nostalgia, but I don't want to make our editors wade through my reminiscences.)

207.2c

We added rulebreaker to the list of ability words, despite its obvious reticence to be included in the rules at all.

608.2g

We added an additional sentence to the end of this rule to clarify the long-held axiom that, when an effect lets a player cast more than one spell during the resolution of a spell or ability, that player may cast those spells in the order of their choice.

614.13a

Before this update, this rule only covered situations where multiple permanents were entering the battlefield simultaneously and an ability that modifies how a permanent enters the battlefield might cause confusing or impossible-seeming choices to appear to be available as part of that ability. (For example, Sutured Ghoul entering the battlefield from a graveyard. This is the rule that stops it from being able to exile itself or any other cards entering from a graveyard at the same time.) We've consolidated the former 614.13b into this rule by allowing this rule to apply to objects entering and leaving any zone, as opposed to just objects entering the battlefield. (If this seems confusing to you, you're right: many situations this rule handles are quite arcane.)

General Double-Faced Cards Organizational Update (includes 701.27, "Transform," 701.28, "Convert, " and 712, "Double-Faced Cards, " and the new 713, "Meld Cards")

With this update, we reorganized and consolidated the rules regarding double-faced cards. Previously, some rules governing double-faced cards were scattered across the document and were often difficult to find, even for folks who were familiar with the structure of the Comprehensive Rules. There are too many individual changes to enumerate, but I'll cover the major update, which includes a small functional change.

When meld cards were introduced in 2016 with the release of Eldritch Moon, they weren't considered double-faced cards. In 2023 with the release of March of the Machine, we decided to move meld cards under the umbrella of double-faced cards. Our rationale at the time was that the distinction between meld cards and double-faced cards was confusing, and since that release introduced cards like Overgrown Pest that specifically referenced "double-faced cards," this would make it easier for players to know what counted as a double-faced card for the purpose of those effects. No other functional changes were made to meld cards due to this recategorization.

In the intervening years, we printed modal double-faced cards that could transform, which meant that some of the distinctions between modal double-faced cards and non-modal double-faced cards (formerly "transforming double-faced cards") eroded. Specifically, we allowed all double-faced cards to transform, with the exception of meld cards. As we reorganized the double-faced card rules for this release, we realized that this change meant that meld cards were, mechanically, almost entirely dissimilar from their counterparts in the double-faced card cohort and that their inclusion in that category no longer made functional sense.

With that in mind, we moved the rules for meld cards out of rule 712, "Double-Faced Cards," and into the new rule 713, "Meld Cards," reverting the change we made in 2023. As such, meld cards are no longer considered double-faced cards. This affects a very small number of cards (such as the aforementioned Overgrown Pest) that interact specifically with double-faced cards in that they no longer interact with meld cards. No other functional changes were made to the rules governing meld cards with this release.

We also pulled rules from outside of these sections into the above listed sections, either leaving references between them or moving them altogether depending on context. Again, there are too many to enumerate, but these changes are organizational in nature rather than functional, with an eye toward making the rules governing double-faced cards easier to find and cross-reference.

Oracle Updates

That Rascally Otter

0012_MTGMBC_ComNew: Tolabow, Loch Rascal

As Jess Dunks mentioned in his August article about Tolabow, Loch Rascal, the printed rules text of Tolabow was hard to understand and had many unintuitive results. After much discussion, we updated Tolabow's rulebreaker ability to be clearer and more intuitive by referencing color identity explicitly.

Old text:

Rulebreaker — A deck with this commander can have instant and sorcery cards of one additional color not in this commander's color identity and any basic land cards.

Whenever you cast an instant or sorcery spell, create a 1/1 blue and red Otter creature token with prowess. (Whenever you cast a noncreature spell, it gets +1/+1 until end of turn.)

New text:

Rulebreaker — If Tolabow, Loch Rascal is your commander, the color identity of instant and sorcery cards in your deck can include one color of your choice not in your commander's color identity, and your deck can have any basic land cards.

Whenever you cast an instant or sorcery spell, create a 1/1 blue and red Otter creature token with prowess. (Whenever you cast a noncreature spell, it gets +1/+1 until end of turn.)