And here we go, March of the Machine isn't even out yet but here's a new fun singleton format for everyone to play, i call it, Siege. It is a 2 - 4 player format in which each player choses a Plane to invade, and builds their deck around their chosen Battle. 

In Siege each player makes an 80 card deck where no cards may be the same (excluding basic lands), and choose one of the new Battle type cards from March of the Machine to use as their Plane of choice. Similar to a commander, Battles exist in their own separate space and may be cast any time their owner has the mana, they also have a tax like commanders, the Battle Tax makes your Battle cost an additional 2 generic mana for each time it has been cast from the Battle Zone in that game. 

Every card legal in commander is legal to play in a Siege deck, although I'd encourage anyone playing to decide what can and can't be played for their own group, because when it comes to unofficial formats anything really goes. 

Cards in your deck must match your chosen Battle's colour identity (for players who aren't sure how to tell on double faced cards, look at the mana symbols on the front of the Battle, and the small circle on the backside of the Battle next to its type line, these together indicate colour identity), decks may also include colourless cards no matter their colour identity. 

Each player begins the game with 30 life. 

When a player damages a Battle in Siege, that damage is also dealt to its "protector," applying on-hit damage as if it had been done to that player. 

Cards that reference a "commander" for their text are treated as if they are referring to your chosen Battle, if your Battle flips into a creature, then cards that say "commander creatures" treat that creature as if it is your commander. 

Those are the rules so far, as I think about and play the format I may change them as needed. 

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The example deck I've made alongside this particular format is for the Battle Invasion of Segovia // Caetus, Sea Tyrant of Segovia that flips into Invasion of Segovia // Caetus, Sea Tyrant of Segovia once Segovia has been conquered. 

Caetus has a really powerful effect for blue, and though you might not think it (unless you've played with Talrand and the Blue token maker gang), blue has some very powerful token generators that we can use to convoke huge non-creature spells. I went for an Instant and Sorcery theme, because a lot of Blue token generation is tied to casting those types of card, but I think it'd be possible to do maybe an Artifact tokens deck in mono-blue as well to cast down some huge threats, I'd certainly love a free Spine of Ish Sah. 

The deck focuses on card drawn and setting up token generators early on before transitioning into some absolutely huge spells. A free Nexus of Fate don't mind if I do, Spelljack? I hardly know it but I'd love an essentially free cast of it. My point here being huge counter spells with crazy upside coupled with game winning extra turns and multi-casts, with Convoke as a newly minted Blue and Red mechanic, spell slinging using your creatures as a cost resource is a new and fun way to play magic. 

Every Battle provides a very different and interesting set of advantages and build arounds, even for the limited number of them that have just been introduced. I'm personally excited to see how Invasion of Theros // Ephara, Ever-Sheltering and Invasion of Theros // Ephara, Ever-Sheltering would work out in this format, but there's so much potential for crazy new ways of playing with a lot of these Battles and I think Siege as a game mode is a pretty fun way to see how it all works out. 

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Below are all currently revealed Battles, I'll update this list as Aetherhub adds more Battles to the database and hopefully the images will be added sooner rather than later for the some of the missing ones;

White:

Blue:

Black:

Red:

Green:

Multicolour:

Colourless: