This format is a player community-created EDH/Commander format that has been around for a few years now, but this is the first time WotC has actually listed it as a playable casual format. In this format, players will build 58-card main decks with an Oathbreaker (a planeswalker card) and a Signature Spell (an instant or sorcery) that matches the color identity of the Oathbreaker.  The Oathbreaker and the Signature Spell start in the command zone at the beginning of each game, and can be can during the game at their normal costs, plus an additional two mana for each time they have been cast.  Both of these cards return to the command zone if they would go to the graveyard.

Oathbreaker is to be played as free-for-all multiplayer for three to five players.  Players start the game with 20 life, and the last player standing wins the game.  If the format takes off, it will likely add to the popularity of planeswalker cards, as they are the engine that drive these decks.

For more information on future releases of Magic products, check out ICv2's 2023 calendar (see "'Magic: The Gathering' 2023 Release Calendar").