Rules – Primordial Format

Deck-building

A Primordial deck must contain at least 40 cards, all cards must come from the same set (reprints are allowed) and:

Exactly 2 mythic rare / rare – not more than 1 of any individual mythic rare / rare
Exactly 6 uncommon – not more than 2 of any individual uncommon
∞ Common – not more than 4 of any individual common, except for basic lands
Up to 8 cards in the sideboard, if used

Additional rules

Archive Rule
- Strixhaven: School of Mages (STX) and Strixhaven Mystical Archive (STA) are treated as though they are one set for Primordial. Cards from STA may be included in a STX deck at their printed rarity in STA. This rule is also true for The Brother’s War (BRO) and The Brothers’ War Retro Artifacts (BRR).
- March of the Machine (MOM) and Multiverse Legends (MUL) are treated as though they are one set in Primordial. Cards from MUL may be included in a MOM deck at their printed rarity in MUL.
- As of this message, the rule is only true of the previously mentioned sets. This rule is not true for sets such as Kaladesh Inventions (MPS) or Amonkhet Invocations (MP2).
Basic lands:
- The following basic lands can be played in any set : Plains, Island, Swamp, Mountain and Forest.
Cards rarity:
- The rarity of the cards depends on the set of your deck.
- The rarity of Timeshifted cards depends on their original set (Arena is considered as rare).
Cards saying, “a deck can have any number of cards named […]”:
- Well, as it is written above… a deck can have any number of these cards (no matter their rarity).
Cards that explicitly refer to another card from another set:
- These cards can be played together, as if they were from the same set (e.g.: Gate to the Afterlife explicitly refers to God-Pharaoh’s Gift).
Sideboard:
- Your sideboard may only contain cards printed in the set of your deck and the “copies of one card” rule, based on rarity numbers, extend across both the mainboard and sideboard (put simply, you can play no more than four total copies of any given common, two total copies of any given uncommon, or one total copy of any rare or mythic rare in both your mainboard and sideboard).

Multiplayer

Primordial is using the free-for-all Commander system for its multiplayer mode. In other words, your deck must still be compliant with the Primordial format deck-building rules (no commander, 1 set, 40 cards minimum, etc.) and your games should look like this:
- 2-6 players
- Free-for-all multiplayer format
- Start with 20 life
- Take turns in clockwise order
- Last player standing wins
Also, as it used to be stated in the Official Commander Rules: “House rules or ‘fair play’ exceptions are always encouraged if they result in more fun for the local community”.