A lot of Magic: The Gathering sets are themed around a specific location in its multiverse. Somewhere with a distinct identity like Innistrad, where it's all Hammer horror movie all the time, or Eldraine, a land of fairytales and legends. The next set is not one of those. March of the Machine is an event set, which is something we haven't seen since War of the Spark back in 2019. It's taking place on a bigger scale, representing the climax of a storyline that's run over the last three expansion sets.
Where things left off in the previous set, which took place in the biomechanical hellscape of Phyrexia, the Mother of Machines seemed to have won. Elesh Norn's plan to launch an invasion across multiple planes simultaneously using a corrupted cosmic tree called the Realmbreaker was successful, and her Machine Legion was poised to conquer and convert the multiverse, borg-ing the inhabitants of world after world, turning them into porcelain-and-metal Phyrexians to conquer yet more worlds with.
The party of planeswalkers who tried to prevent that failed, and many of them ended up Phyrexian-ized themselves. It's not over yet, though. A final team-up of planeswalkers and legends from across the multiverse still stands against the Machine Legion, and war is being fought across dimensions.
One way March of the Machine represents that is with cards that combine two existing characters, fighting side by side. These match-ups highlight unusual alliances, like Drana and Linvala, a vampire and an angel, or Yargle and Multani, a giant frog and a living tree who is also a wizard. Each one is an Odd Couple in their own way. Since the teaser trailer shows one of the gingerbread people from Eldraine, here's hoping she gets her own card—maybe teaming up with a Colossal Dreadmaw or something.
Mechanically, everyone working together will be represented by the new backup mechanic, which lets some creatures give bonus abilities alongside a +1/+1 counter, with those bonuses differing based on the creature's type. On the Phyrexian side, the invaders have incubators, artifact cards that transform into creature cards for a cost of two mana, letting them drop a bunch of pods to sit there menacingly before hatching into monsters.
March of the Machine also introduces the first new card type seen in Magic: The Gathering since planeswalker cards were added in 2007. Cards with the battle type are double-faced, and flip from their initial form into something more powerful when defeated. The twist is, rather than your opponent being the one to attack them, your opponent will be trying to protect them—you have to fight your own battles if you want to get stronger.
To represent the multiversal nature of the conflict, March of the Machine brings back support for the planechase format. This variant gives each player a separate deck of oversized planechase cards, each representing how a specific location affects magic, or some phenomenon of planar travel. For instance, the city of Towashi on the cyberpunk Japanese plane of Kamigawa gives all modified creatures trample, because if you're going to unleash monsters in a Japanese city you have to expect them to turn into Godzilla.
In planechase you also have the option to roll a "planar die" on your turn, for an increasing mana cost. Four times in six nothing happens, but the one time in six you roll the planeswalker symbol, you get to replace the current planechase card. The one time in six you roll the chaos symbol, well, chaos ensues, triggering some outlandish additional effect of the current planechase card.
A deck of planechase cards and a planar die will be packaged with each of the five commander decks releasing with the new set. March of the Machine will be available across the usual variety of booster packs, with draft, set, and collector boosters also containing Multiverse Legends cards, reprints of classics like Ragavan, Nimble Pilferer that won't be legal in standard format, but will be game changers in draft.
Prerelease events for March of the Machine run from April 14–20. It arrives in Magic: The Gathering Arena on April 18, and in paper Magic on April 21. A smaller epilogue set of just 50 cards called March of the Machine: The Aftermath will follow in both digital and physical editions of Magic on May 12.