Legacy 12-Post – Deck Guide

What used to be known as “12-Post,” decks built around the card Cloudpost, have existed in Legacy for quite some time. Like many of the decks I do deck guides on, this deck has received substantial improvements over the years and has been putting up some consistent results on Magic Online. While there are a lot of different ways to build this deck, the mono-green approach has been one of the more popular variants as of late. 

This past weekend, Magic Online player Angers put up a Top 4 finish in one of the weekend Challenges with a solid looking list. This list has a lot of specific numbers, so let’s jump right in and take a look at what role each card plays.



Legacy 12-Post by Angers



Header - The Game Plan

In many ways, this is the Tron of Legacy. It’s a linear deck focused on getting as many of its namesake land into play as soon as possible by playing and copying Cloudposts as fast as possible. This will allow the deck to cast massive, game-ending spells like Ulamog, the Ceaseless Hunger rather quickly, which will generally take over most games. It has a lot of ways to tutor for specific lands, and with cards like Golos, Tireless Pilgrim, it’s no longer necessary to accumulate an infinite amount of mana, as just being able to activate Golos will swing a game in your favor.


Header - Card Choices

Elvish ReclaimerExpedition Map

These are the consistent ways to ensure that you can find the lands you need. Expedition Map already has a long pedigree of searching up Urza’s lands in Modern. Here, they serve the same purpose and really help ensure that you can develop consistently. 

Elvish Reclaimer is a relative newcomer to the deck, but this deck makes excellent use of it. While it does open the deck to removal to some degree, the impact it has certainly outweighs the downsides. It significantly increases the consistency of the deck by providing access to Cloudpost if you ever untap with it. Beyond that, it has the potential to meaningfully impact the board, as a 3/4 escapes Lightning Bolt range and can hold back some creatures and pressure planeswalkers.

Some Cloudpost decks play Crop Rotation to be a bit faster and more efficient than these two cards, but the risk of being two-for-one’d by countermagic can make it quite a bit more costly.


Ancient Stirrings (Timeshifted)Once Upon a Time

These serve to further increase the consistency of the deck, and are part of the reason this deck can keep up with the rest of the format. In many ways, these are like the Brainstorm and Ponder of this archetype, being able to find most of the pieces you might be missing to get started. While Once Upon a Time is certainly the card you want in your opening hand more than almost any other card, playing four copies can be costly because only the first one is free (most of the time). On the other hand, Ancient Stirrings is cheap enough to be cast early to find a missing Cloudpost or later and still cast the payoff spell you found off of it.


Golos, Tireless Pilgrim

One of the other newcomers to the archetype, Golos is a heavy hitter in this archetype. You might have picked up on a trend, but like every card discussed previously, Golos can easily search up missing Cloudposts to give you an absurd amount of mana.

Beyond that though, Golos represents a potent threat of activation. Searching up The World Tree will often allow you to activate Golos on the following turn which, in this deck full of haymakers, threatens to take over the game. Beyond these two options though is a plethora of lands to search up for just the right situation.


Green Sun's ZenithPrimeval Titan (Timeshifted)Ramunap Excavator

This version of the deck has a small Green Sun’s Zenith package, which again, greatly increases the consistency. Searching up Elvish Reclaimer will help you get the ball rolling early on. Later in the game, Primeval Titan will easily take over the game if it resolves. The deck used to be centered around getting Titan into play as fast as it could, but with the inclusion of Golos (which is substantially easier to cast), it isn’t quite as necessary anymore. Ramunap Excavator is mostly a way to counteract Wasteland strategies, but it has some additional utility of working with Elvish Reclaimer.


Ulamog, the Ceaseless HungerEmrakul, the Aeons Torn

Since Cloudpost can generate such absurd amounts of mana, these are some of the best payoffs Legacy can offer. Ulamog ends the game in short order and will generally be able to shore up any specific issues that are occurring on board. The fact that it’s exile effect can’t be prevented by most countermagic in Legacy (Stifle excluded) means that most issues will be solved just by casting it. Emrakul is quite a bit more difficult to cast, as 15 mana is no joke, even for this deck. However, by having access to it in the deck, it means that Eye of Ugin will have the ability to end the game on the spot if given enough mana.


Ugin, the Spirit DragonBoompile

I’m classifying these as the board sweeper category of cards, although Ugin, the Spirit Dragon does more than that alone. In a game of Legacy that cares about board presence, a resolved Ugin will most certainly be the most powerful thing in that game.

However, not all Legacy decks care about that axis of the game, so Ugin might not have as much of an impact as you might want. In addition, it still costs eight mana and needs to resolve to have an impact, so cards like Spell Pierce and even Daze can make things challenging for Ugin. That’s why this deck only plays a single copy, although more copies aren’t out of the question.

Boompile is a weird one, and although I have played this in my Commander decks before, I’ve actually never seen it show up in Legacy. Leaving your board sweeper up to a 50 percent chance is admittedly pretty poor odds, but on a four-mana card, it’s tough to get much more efficient than that. Oblivion Stone is incredibly mana intensive, so relying on that in Legacy is a tough ask, but Boompile is efficient enough to do the necessary job (50 percent of the time).


Warping Wail

There are a decent number of spells and creatures this interacts with and colorless decks don’t have that many options when it comes to disruption. Warping Wail does a fine job in a lot of situations, but has the failsafe of providing a burst of mana, if nothing else.


Pithing Needle

I’ve talked about Pithing Needle in Legacy before, as it’s a diverse answer to a variety of problematic cards. In this deck, its primary function is to name Wasteland, as that’s the number one most difficult card to deal with for this deck. Needle is very rarely dead, though, so even if you don’t expect Wasteland, it’ll probably have some use.


CloudpostGlimmerpostVesuvaThespian's Stage

These are the namesake cards for the strategy and the core mana engine of the deck. Between the four Cloudposts and the five ways to copy it, it’s relatively straightforward to get two to three copies of the card into play. Glimmerpost further increases the ramp potential of Cloudpost, as it’s also a Locus. Glimmerpost’s inclusion isn’t simply for that purpose though, as the life gain it provides can be crucial to surviving against aggressive decks. It gives the deck a sort of fog/ramp feeling in a lot of games.


Eye of Ugin

This is one of the most important cards in the deck, as it provides this deck an incredible late game. By the time you have enough mana to activate it, you’ll likely be able to get Ulamog, and starting a chain of searching up Ulamog every other turn for a few turns is going to end most games in short order. This deck has plenty of ways to tutor it up, so finding it won’t be a problem by the time you need it.


The World Tree

This is primarily a tutor target for Golos so you can make sure that Golos can be activated the turn after you play it. It’s a bit easier to use than Cascading Cataracts and has some more function earlier in the game, which is why it sees play here.


KarakasBojuka Bog (Timeshifted)Glacial Chasm

This is a pretty neat package of lands to include in any deck with Elvish Reclaimer. Each of them serve a crucial purpose in the games that you need them in (Karakas bouncing Emrakul, Bog dealing with graveyard decks and Chasm buying a lot of time).


ForestWindswept HeathWooded Foothills

Basics always go a long way in Legacy, and it’s no different here. The fetches do expose you to Stifle a little bit, but with Reclaimer and Ramunap in the deck, they can provide a decent amount of extra value being in the graveyard.


Header - The Sideboard

Collector OupheReclamation Sage (Timeshifted)

We’ve seen this type of package in Green Sun’s decks before, and they serve a crucial role when it comes to answering a variety of artifacts and enchantments. Be careful with Ouphe, because while it might be necessary to turn off cards like Lion’s Eye Diamond, it does turn off your Expedition Maps as well.


Krosan Grip

Cards like Blood Moon and Back to Basics are problematic enough that a single Reclamation Sage won’t really cut it. Krosan Grip is one of the best answers to those cards around, which makes it an extremely valuable sideboard card.


Crop Rotation

I mentioned Crop Rotation earlier being a bit too costly at times in the main deck. It’s an excellent sideboard card though, providing additional access to the key lands you need in certain matchups. The downside isn’t as high as a sideboard card, as the lands you’re tutoring up are often more important than losing a little bit of value.


Faerie Macabre

With Bog in the main deck, it isn’t as important to overload on graveyard hate, especially since Crop Rotation serves as extra copies. However, it can be really important to stop decks like Reanimator from going off early, and Faerie Macabre does so in a way that can be difficult to stop.


Mindbreak Trap

Like most non-Force of Will decks, this deck definitely struggles against decks that can combo off very early, so Mindbreak Trap helps keep that in check to some degree.


Spatial Contortion

Extra removal spells are important in Legacy with the presence of decks like Delver and Death and Taxes. Spatial Contortion interacts early enough to keep the early pressure off of you and with Cloudpost tapping for multiple mana, it functions kind of like a one-mana spell.


Header - Tips and Tricks

  • Golos can tutor up Karakas to provide a land tutor engine if you think Golos might be at risk of dying (this is especially good if you have a backup Golos in hand and expect the first to die).
  • Thespian’s Stage can copy your opponents lands as well, so always keep your targets in mind (especially if they have Dark Depths in play).
  • Eye of Ugin isn’t limited to Eldrazi, and if you need to get Golos, that’s an option that is available to you.


Header - Sideboard Guide

Izzet Delver

Izzet Delver

Out: 1 Emrakul, the Aeons Torn, 2 Boompile

In: 3 Spatial Contortion


The combination of Wasteland and pressure is a lot to overcome, but bringing in the extra removal spells helps a lot. It might seem bizarre to bring out a wrath against them (and I’m willing to believe that’s wrong) but Delver is nothing if not a consistent, efficient deck. Placing all your cards on a 50 percent chance is a bit too risky in this matchup, especially when you might only catch a single creature. Beyond that, stopping Wasteland can be really important in this matchup, and Boompile might destroy your own Pithing Needle.





Out: 1 Glacial Chasm, 0-2 Warping Wail, 0-2 Pithing Needle

In: 1 Reclamation Sage, 2-3 Krosan Grip


This is a very good matchup, but Back to Basics out of the board can be pretty devastating. I think you always want to bring in Reclamation Sage to play it safe, but it’s probably reasonable to bring in a few Krosan Grip for additional safety.





Out: 1 Glacial Chasm, 2 Boompile, 1 Ramunap Excavator

In: 3 Mindbreak Trap, 1 Collector Ouphe


This is a nice contrast to Miracles because this is a very bad matchup. There are very few cards outside of Warping Wail that affect their strategy and Cloudpost generally takes too long to get going and is still relatively exposed to Force of Will. It might be wrong to bring out the Excavator just because it attacks and is somewhat cheap, but it doesn’t have much impact in the matchup beyond applying pressure.





Out: 1 Pithing Needle, 2 Warping Wail, 1 Ulamog, the Ceaseless Hunger

In: 2 Crop Rotation, 2 Faerie Macabre


Hogaak is a fast deck, but a lot of what Cloudpost does line up somewhat well against them. As long as Emrakul is in your deck, Altar of Dementia can’t straight up kill you and having Elvish Reclaimer and Crop Rotation give you access to Bojuka Bog pretty consistently. You can even sacrifice the Bog to Reclaimer and use Ramunap Excavator to replay it.

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