Legacy Mono-Black Helm Combo – Deck Guide

While Ragavan hit the ground running early and became the frontrunner of Modern Horizons 2, the roster of powerful cards in that set runs deep. We’re still seeing innovation months later and this past weekend, Magic Online player Paragon249 got second place in a Legacy Challenge with a Mono-Black Dauthi Voidwalker deck. This Helm combo deck is quite different from the other mono-black offerings in the format (such as Curses or Pox) and it’s exciting to see someone succeed with a relatively novel deck. 

Today we’ll take a look at this deck and go over the pretty unconventional card choices that make the deck work.




Legacy Mono-Black Helm Combo by Paragon249


Header - The Game Plan

This is a relatively linear combo deck that’s trying to combine cards like Leyline of the Void and Dauthi Voidwalker with Helm of Obedience in order to one-shot your opponents. Using cards like Dark Ritual and Mox Diamond, it can accelerate into the combo early on, which will force opponents to have interaction early or lose. It also takes advantage of Opposition Agent, which is a relatively underplayed disruptive creature that can put opponents in a bind. If all else fails, this deck has a fair amount of grindy elements, such as planeswalkers and Urza’s Saga, which will provide a substantial edge as the game develops.

Let’s take a look at the individual cards that help this deck come together.


Header - Card Choices

Leyline of the Void (Timeshifted)Helm of Obedience

Leyline is generally a pretty game-changing effect in Legacy. This is especially true now, with Murktide Regent and Dragon’s Rage Channeler running roughshod over the format, thus making Leyline effective against both fair and unfair decks. In this deck, Leyline is also a key combo piece, combining with Helm of Obedience to win the game on the spot. This one-two punch can allow this deck to win as early as turn two in some cases and since they’re both four-mana permanents, they’re pretty difficult for opponents to remove from the board. Helm has the upside of being an artifact, so by running the fourth copy in the board you can make sure you always have access to it with Karn, the Great Creator.


Dauthi Voidwalker

Voidwalker is an excellent card that hasn’t really broken into Legacy yet and it does a lot in this deck. It combines with Helm of Obedience when you don’t have a Leyline of the Void, which provides a fair amount of consistency (there are functionally eight copies of Leyline and seven copies of Helm, if you count Karn). In addition, Voidwalker is a cheap creature that threatens to steal some of your opponent’s spells if you untap with it. This deck doesn’t have discard effects, so you’re not particularly likely to take something like Emrakul. However, taking cantrips or removal spells can be pretty important. Finally, it’s a form of graveyard hate, so against the variety of fair and unfair decks that utilize the graveyard, a fast Dauthi Voidwalker can really shut down their game plan.


Karn, the Great CreatorKarn, Scion of Urza

Karn, the Great Creator has proven itself to be one of the best cards for this style of deck. It threatens to lock the game out all by itself by getting Mycosynth Lattice. In addition, there are a variety of lock pieces that can make your opponent’s life difficult, such as Ensnaring Bridge and Liquimetal Coating. This deck also has some utility inclusions, such as Crucible of Worlds, which can be a powerful engine when paired with Urza’s Saga. The nature of Karn is very versatile, too, so you can tune the sideboard with whatever options you think you’ll need.

Karn, Scion of Urza, on the other hand, isn’t quite as versatile, but it’s a really powerful threat against a lot of decks trying to play fair. As Urza’s Saga has demonstrated, producing a pair of huge artifact threats can really take over a board. The card advantage is nothing to scoff at, too, as moving up with Karn right away will make it pretty difficult to remove as it starts drawing you some key cards.


Opposition Agent

When Opposition Agent was printed, it seemed as if it was going to make waves in Legacy, but that really hasn’t been the case. In most cases, it’s a bit like a slower version of Stifle that has some upside against decks like Doomsday and Death and Taxes. Since this deck is playing Dark Ritual, though, it’s quite a bit stronger here as casting it early may provide you a sort of permanent Stifle effect (that still has upside against different combo decks). It’s an extra dimension of the deck that needs to be respected and will occasionally win games by itself if cast early enough.


Maralen of the Mornsong

This is a pretty unconventional choice but in conjunction with Opposition Agent, it’s a way to lock your opponent out of their draw step (since now you tutor their deck for a card). On its own, it’s a very risky card to play, since your opponents are likely to tutor the perfect answer (or a combo piece), so you have to be extremely careful when casting this on an empty board.


Dark Ritual

Dark Ritual is one of the most powerful cards in Legacy and, truth be told, there aren’t that many decks that fully take advantage of it. In this deck, which is built around slower, powerful permanents that can end the game on the spot, it’s the perfect inclusion. 


Mox Diamond

This deck plays a lot of lands, so running Mox Diamond as a form of acceleration isn’t too high of a cost. While the card disadvantage shouldn’t be ignored, the effect it provides is pretty important since this deck has a lot of slower, more expensive cards. A lot of this deck’s strongest draws will involve either Mox Diamond or Dark Ritual, so it’s a pretty important card to see in your opening hand. Additionally, since this deck has Crucible of Worlds in the sideboard to tutor with Karn, you can offset the downside pretty easily.


Pithing NeedleExpedition MapRetrofitter FoundryShadowspearThe Underworld Cookbook

These are the Saga targets, and there are more here than usual. Needle, Foundry and Shadowspear are pretty common, each serving their purpose quite well. Map makes a lot of sense in a deck with this many different utility lands (and in matchups where chaining Sagas is the best strategy). The Underworld Cookbook is quite uncommon, though, but it does have its uses. On its face, acting as a way to gain life can be meaningful, as well as returning one of your key creatures. On top of that, discarding lands and replaying them once Crucible of Worlds is online is a nice life gain engine, so the Cookbook certainly has its uses.


Serum Powder

Since this deck is trying to assemble a relatively linear combo, having Serum Powder will help it happen far more often. You should use it somewhat liberally most of the time you don’t have the pieces you need. On top of its primary use, it’s also a bad mana rock, which might be something you’re in the market for in some of the games.


Urza's Saga

A card that needs no introduction, Saga is the glue that keeps decks like this functioning at capacity. It provides an alternate plan that opponents can’t easily interact with and has the ability to take over a game by itself. Saga is just one of the best cards in the format and it plays a significant role at making this deck work.


City of TraitorsAncient Tomb

This is actually a different split than we usually see, seeing as Ancient Tomb sticks around and City doesn’t. It makes sense here, though, since Karn is pretty likely to tutor up a Crucible of Worlds and the life loss will add up. Plus, with Mox Diamond in the mix, you might not ever have to play a land in order to keep developing your mana, which is some nice upside.


Blast ZoneInventors' Fair

These are some value lands that act as tutor targets off of Expedition Map, and act as engines with Crucible of Worlds in play. Blast Zone is an excellent (albeit slow) answer to all sorts of permanents that pose problems, especially when they cost one or two mana. Inventors’ Fair is primarily a way to search up Helm of Obedience, which adds some extra consistency to the deck.


Silent ClearingIfnir Deadlands

These are some “free” value lands to play over Swamps. Paying a life is a cost, for sure, so they’re not actually free, but it’s low enough that they add more than they take away a lot of the time. Silent Clearing helps you out if you’re flooded and Deadlands can take care of pesky small creatures that are applying pressure. Since both of them have to sacrifice to activate, they work nicely with Crucible of Worlds.



Karakas is still one of the best lands in the format and outside of Dauthi Voidwalker, it’s not that large of a cost to run a “colorless” land.


Swamp (#272)

Basics are awesome in Legacy, so running a ton of them is quite nice.


Header - The Sideboard

Helm of ObedienceCrucible of WorldsDefense GridLiquimetal CoatingMycosynth LatticeSphere of AnnihilationWalking Ballista

These are the Karn tutor targets that will basically never leave the sideboard. You always want access to them when you play Karn and each serves a different role. Helm is the extra combo piece, Crucible makes up an engine and Defense Grid provides protection. Meanwhile, Coating/Lattice are lock pieces that pair well with Karn and Sphere/Ballista are there for creature matchups.


Karn, Scion of Urza

There are a lot of matchups where you want a grindy planeswalker that plays to the board. It sidesteps a lot of the hate that people will bring in against you and plays to the board quite well.


Ensnaring Bridge

This is pretty much always a tutor target, but playing a second copy means you can board it in when you think you need it (say, against Show and Tell decks).


Plague Engineer

Plague Engineer has fallen off a lot as of late, but it’s still a great card. It doesn’t get much better than Engineer when it comes to killing small creatures and there are plenty of matchups where you will want this.


Sudden Edict

Sudden Edict hasn’t seen too much play since its printing, but it’s a solid removal spell that can sidestep some awkward situations (such as Knight of the Reliquary activations).


There are a lot of cards you can play here, but this is a solid wrath if you expect smaller creatures. The life loss/gain can be relevant, so this card definitely has its place.


To the Slaughter

This is a nice way to pick up a clean two-for-one against decks that have both creatures and planeswalkers. There are a ton of other options you can play here, but this card definitely serves a role.


Header - Tips and Tricks

  • If you exile a Helm of Obedience with Karn, Scion of Urza, Karn, the Great Creator can put it back in your hand if the sideboard copy has been countered/killed.
  • If you have both Leyline and Dauthi on the board at the same time, you can choose what happens to cards that would get exiled.
  • If you think they have relevant creatures in their deck, you can always Helm of Obedience them without Leyline in play to try to put a creature into play.


Header - Sideboard Guide


Izzet Delver

Izzet Delver

Out: 1 Pithing Needle, 1 The Underworld Cookbook, 1 Maralen of the Mornsong, 4 Opposition Agent

In: 1 Karn, Scion of Urza, 1 Ensnaring Bridge, 1 Sudden Edict, 1 To the Slaughter, 1 Meathook Massacre, 2 Plague Engineer


Outside of fetchlands, they don’t really tutor too often, so Opposition Agent falls off in value pretty sharply. They tend to bring in a fair amount of artifact hate, as well, so turning to Karn, Scion of Urza can give you a lot of staying power. Murktide Regent is problematic, for sure, but Ensnaring Bridge helps a fair amount (as well as Leyline doing work there). There are enough tools here that it shouldn’t be too tough to grind them down, but they can definitely keep up with you so be careful not to fall too far behind.



Bant Control

Bant Control

Out: 1 The Underworld Cookbook

In: 1 Karn, Scion of Urza


You don’t really need to overboard here. A lot of what the deck does lines up well with Bant Control, especially considering that Prismatic Ending has some difficulty in answering your combo pieces. Try to get a Karn down quickly and if that fails, relying on Urza’s Saga to dominate the board is effective here.



Death and Taxes

Death and Taxes

Out: 1 The Underworld Cookbook, 3 Leyline of the Void, 2 Helm of Obedience

In: 1 Sudden Edict, 2 Plague Engineer, 1 To the Slaughter, 1 The Meathook Massacre, 1 Karn, Scion of Urza


Relying entirely on the combo is risky here. Leyline itself has no effect in the matchup and on top of that, they have clean answers to all your combo pieces. I think turning into a mono-black control deck that seeks to use planeswalkers and Urza’s Saga to take over the game makes more sense, but I wouldn’t cut the combo entirely.





Out: 1 The Underworld Cookbook

In: 1 Defense Grid


One of the few matchups where boarding in a tutor target makes sense, seeing as the matchup can be very fast. This is a tough deck to play against since your combo is slower than theirs and there aren’t too many relevant lock pieces. Of course, Opposition Agent is very strong here, but they have plenty of disruption to keep that from ending the game right away (although if it hits play Game 1, it will likely be lights out). Try to race them as much as you can and I would Serum Powder quite aggressively to put together a fast hand or an early Opposition Agent.



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