Wizards of the Coast (WotC) has officially recognized Oathbreaker as a Magic: The Gathering format.
Oathbreaker, a fan-made multiplayer format, was created in 2017 and plays similarly to Commander but with a few tweaks. Players use 60-card singleton decks, but instead of having a legendary creature helm the deck, players choose a planeswalker and a signature spell (an instant or sorcery) to keep in the command zone. Cards in the deck have to follow the planeswalker, or Oathbreaker’s color identity — the same goes for the signature spell.
Just like in Commander, players can cast their Oathbreaker or signature spell multiple times in a game, with each subsequent casting of it increasing its mana cost by two generic mana. The only cards a deck can have more than one copy of is basic lands. The game is designed for three to five players. The Oathbreaker and signature spell are considered part of the deck, so players need a 58-card main deck.
If your Oathbreaker would be put into your library, hand, graveyard, or exile from anywhere, you may return it to your command zone instead. As long as your Oathbreaker is on the battlefield, you can cast your signature spell from the command zone. Your signature spell will also return to the command zone after it resolves or it goes anywhere else.
The Oathbreaker dedicated website has rules, history, starter deck ideas, an FAQ, and a banned list. Currently, no planeswalkers are banned, so players can build a deck around any black-bordered planeswalker in the game. There is, however, a banned list that keeps the format from being too explosive or combo-centric. Obvious inclusions are the five original moxen, Black Lotus, Ancestral Recall, Time Walk, as well as Sol Ring, Time Vault, Channel, Tinker, and more.
The Oathbreaker Banned List can be seen below:
- Cards with the “Conspiracy” card type. Click here to see those.
- Cards that reference “playing with ante”. Click here to see those.
- Silver-bordered cards
- Ad Nauseam
- Ancestral Recall
- Balance
- Biorhythm
- Black Lotus
- Channel
- Chaos Orb
- Cleanse
- Crusade
- Dark Ritual
- Doomsday
- Emrakul, the Aeons Torn
- Expropriate
- Falling Star
- Fastbond
- Gifts Ungiven
- Griselbrand
- High Tide
- Imprison
- Invoke Prejudice
- Jihad
- Jeweled Lotus
- Library of Alexandria
- Limited Resources
- Lion’s Eye Diamond
- Mana Crypt
- Mana Geyser
- Mana Vault
- Mox Emerald
- Mox Jet
- Mox Pearl
- Mox Ruby
- Mox Sapphire
- Natural Order
- Painter’s Servant
- Pradesh Gypsies
- Primal Surge
- Saheeli, the Gifted
- Shahrazad
- Sol Ring
- Stone-Throwing Devils
- Sundering Titan
- Sylvan Primordial
- Time Vault
- Time Walk
- Tinker
- Tolarian Academy
- Tooth and Nail
- Trade Secrets
- Upheaval
- Yawgmoth’s Bargain
Read the official article on the format from WotC and check out the fan-site for Oathbreaker to get started playing.