MBC · Player guide
mystery booster commander rules
Mystery Booster Commander Edition adjusts Partner in Commander Draft and introduces Rulebreaker permissions that cross Commander color identity restrictions. [Release notes] It also introduces types and counters, while Playtest cards are limited to this set's Draft and Sealed events. [Set reference] [Playtest restriction]
| Item | Treatment in this set |
|---|---|
| Rulebreaker | A new mechanic on 8 cards allows cards outside a commander's color identity. [Source] [Release notes] |
| Rulebreaker design | The Commander Format Panel participated in the design. [Source] |
| Partner in Commander Draft | In Commander Draft, a commander without Partner whose color identity contains one or fewer colors may be treated as having Partner. [Release notes] |
| Planeswalker types | 7 new types: Arzakon, Dyfed, Feroz, Greensleeves, Sifa, Thomil, and Worzel. [Source] |
| Creature types | Homarid is retired and replaced by Lobster. [Source] |
| Odor counter | Introduced in this set. [Source] |
| Contract counter | Introduced in this set. [Source] |
| Tide counter | Returns for the first time since Fallen Empires. [Source] |
| Playtest restrictions | The 121 Playtest cards can be used only in this set's Draft and Sealed events. They are not legal in any Constructed format. [Release notes] |
Deck construction
Partner in Commander Draft and Rulebreaker
The Partner adjustment
In Commander Draft, a commander without Partner whose color identity contains one or fewer colors may be treated as having Partner. [Release notes]
| Condition | Treatment in this set |
|---|---|
| Play context | Commander Draft. [Source] |
| Existing ability | The commander does not already have Partner. [Source] |
| Color identity | One or fewer colors. [Source] |
| Permission | May be treated as having Partner. [Source] |
Rulebreaker
Rulebreaker allows cards outside a commander's color identity, directly changing deck construction rules. [Release notes]
Types and counters
New types and returning terminology
| Item | Treatment in this set |
|---|---|
| Planeswalker types | 7 new types: Arzakon, Dyfed, Feroz, Greensleeves, Sifa, Thomil, and Worzel. [Source] |
| Creature types | Homarid is retired and replaced by Lobster. [Source] |
| Odor counter | Introduced in this set. [Source] |
| Contract counter | Introduced in this set. [Source] |
| Tide counter | Returns for the first time since Fallen Empires. [Source] |
Card eligibility
Playtest cards are not legal in Constructed formats
The 121 Playtest cards can be used only in this set's Draft and Sealed events. They are not legal in any Constructed format. [Release notes]
This includes Constructed Commander. [Release notes]
Player questions
Frequently asked questions
Which commanders can be treated as having Partner in Commander Draft?
In Commander Draft, a commander without Partner whose color identity contains one or fewer colors may be treated as having Partner. [Release notes]
Can Mystery Booster Commander Playtest cards be used in Constructed Commander?
The 121 Playtest cards can be used only in this set's Draft and Sealed events. They are not legal in any Constructed format. [Release notes]