The Essential Deck Primer for Legacy Grixis Breach Delver

Since the release of Theros Beyond Death I’ve been working on a range of incredibly fun decks. The one that really stood out has been Grixis Breach Delver. After showing him my first build and results of Grixis Breach Delver, my teammate Kasper Euser and I have been exploring the options for the deck. The win rate of both myself and Kasper has been excellent throughout this process. And when we got to our first paper tournament, Kasper took down the Dutch Open Series with the list, going undefeated throughout the Legacy Open, and marking the first high-profile finish for Grixis Breach Delver.

Pete van der Ham winner photo

This deck is incredibly engaging and fun. I would love to encourage people to pick this deck up, as it’s the most fun I’ve had in Legacy playing a competitive deck. Largely because of discovering all the subtle interaction within the deck, but also because it’s one of the most skill-intensive decks with regards to strategic gameplay. I know that a being hard to play deck definitely isn’t a good quality when discussing how good or viable a deck is, but it sure makes it interesting to play. It also helps that this deck can be even more challenging to play against as it is to play with.

This primer is meant as a general introduction to the deck, as well as to address why I think this particular build can exist in the meta (it’s raison d’être), some of the interaction that make it so much fun, a guideline for playing with the combo, and justification for the current inclusions and exclusions.

Finding a Shell

Before I get into the details. Here’s our current list, and the one I’d suggest for players to use as a starting point.

Grixis Breach Delver Deck List
Click to enlarge.

The reason this deck exists is that the core of the Breach combo is incredulously powerful—but significantly harder to protect than traditional combo plans in Legacy. It’s vulnerable to countermagic, enchantment destruction, graveyard hate, and (to some extend) discard. This makes builds that go all-in on the Breach combo unattractive, to me; and led me on a search to harness the power of this combo in different ways. While trying out some focused Underworld Breach combo decks, it also became apparent how strong some enablers are, and how unnecessary everything around it was.

The current Underworld Breach combo design we’re using is such that we add in the minimally required amount of combo pieces (Brain Freeze and Underworld Breach) and focus on none but the most powerful enablers (Lion’s Eye Diamond and Infernal Tutor). We can then optimize the rest of the main deck for when we operate outside of the combo.

Why play the Breach combo in Delver, instead of any other shell?

There are a couple of key factors that led me to this selection:

  • The first, and most important, is that it’s important we choose a shell that contains cards like Ponder, and more importantly Brainstorm. These cards allow us to search for specific pieces when our hand or the game-state dictates it, while getting rid of the ones that don’t line up to the scenario we find ourselves in.
  • The second direction is driven by the fact that we want our two plans to ask for different answers. For example, our opponent would bring in countermagic and discard spells against both control and against combo.
  • Our third direction is the incentive that we want to punish our opponent for drawing the wrong answers against our hand, before they get a chance to sculpt the correct answers. This is why we would like a proactive plan.
  • Finally, and the least avoidable, we need our shell to include at least blue for Brain Freeze, red for Underworld Breach, black for Infernal Tutor to utilize the aforementioned most powerful enablers and smallest combo plan.

Delver of Secrets // Insectile AberrationYoung Pyromancer

We trade the vulnerable but powerful card advantage engine that is Dreadhorde Arcanist for a distinctly more powerful but similarly vulnerable combo. Our aggressive cards that can close out a game ultimately remain unchanged.

People have been asking me “what is the plan post-sideboard, is it a combo or a Delver deck?” To which I’ve answered simply, “both.”

While split game plan decks have existed in the past, they have largely been unsuccessful. In my experience this is because, within each game and when sideboarding, the split plan player had to choose which path to follow—and hope that their opponent prepares for the wrong part. This deck gets its strength from having all game plans be serviceable in any of our games. While the deck sometimes stumbles due to discord within its pieces, that is more than made up for by the power level that resides in both plans, and the hoops our opponents has to jump through with their limited information about the cards we have access to in any specific scenario. I’ll also specifically address the crossover between the plans, and each combo pieces’ utility for the fair Delver game plan in part below. But first, an introduction to the Underworld Breach combo.

The Combo: Basics

This is the lowest resource spell-based combo available in Legacy. While you’re generally not looking for an early combo, it should always be on your mind how far you are from executing your combo. Certain hands do allow you to combo early, which can be backbreaking for your opponent. In this part of the primer, I’ll give some basic examples of the requirements to win the game with your combo, but keep in mind that a lot of your cards can impact these basics—so it’s good to look for opportunities and risks when planning the game toward a combo turn. On average, Grixis Breach Delver tends to win with the Underworld Breach strategy just over half of its games; but it can also win a tournament without executing the combo more than a couple of times.

Lion's Eye DiamondInfernal TutorUnderworld BreachBrain Freeze

On the surface, the requirements to go off (unprotected) are as follows: Have an Infernal Tutor, a Lion’s Eye Diamond, and a total of nine other cards between your hand and graveyard. If you have this, you can get to a point where you are able to Brain Freeze yourself with an Underworld Breach in play. Once you resolve Brain Freeze and its storm copies targeting yourself, you have enough cards in your graveyard to cast all the spells in your deck, including additional Brain Freezes. How the numbers and combo work up to that point is illustrated in the table below.

Infernal Tutor + Lion’s Eye Diamond, two mana, nine-card Underworld Breach combo

Infernal Tutor + Lion's Eye Diamond, two mana, nine-card Underworld Breach combo
Click to enlarge

Note 1: This is the number of cards required between your hand and graveyard, in addition to the combo pieces.

After the last step of this sequence you can escape your entire deck, opponents should usually scoop when you target them with some copies of Brain Freeze to preserve information. But the safest kill is to just Lightning Bolt them a number of times. This is done by cracking Lion’s Eye Diamonds for red and escaping Lightning Bolts. To win in this manner requires your number of remaining cards to be more than your opponent their life total + 3 cards for each 9 damage to generate the required red mana.

To translate the setup to practical situations, you’d need access to 11 cards between your hand and graveyard, including Lion’s Eye Diamond and Infernal Tutor. Here are some of the ways to meet these requirements on turn 2:

  • On the play with Thought Scour and two fetch lands: Turn 1 play and use a fetchland (+0) and cast Thought Scour targeting yourself (+3 cards), turn 2 draw a card (+1) and play and use a second fetchland (+0 card); adds up to 7 + 3 + 1 = 11 cards.
  • On the draw with Thought Scour and one fetchland: Turn 1 you draw a card (+1), play and activate a fetchland (+0), and then Thought Scour targeting yourself (+3 cards). On turn 2 you draw another card (+1) and play a land from your hand (-1); which leads to a total of 7 + 1 + 3 + 1 – 1 = 11 cards.

The above two examples for a turn-2 combo should illustrate that there are only a few ways to get a turn-2 combo—if you only have Lion’s Eye Diamond and Infernal Tutor to work with. Keep in mind that winning with the combo on the early turns get significantly impacted by mulligans, and the number of cards you put onto the battlefield. If you’re looking for ways to get enough fuel for the combo on turn 3 and later, you find that you are slowly finding more ways to set up the Underworld Breach combo.

When you allow yourself to access a third mana for your combo (i.e. three lands in play), the requirements to execute the combo drop drastically—as you’d require one fewer Lion’s Eye Diamond escape to get to your first Brain Freeze. The requirements and line that follows when you start with three lands is illustrated below.

Infernal Tutor + Lion’s Eye Diamond, three-mana, six-card Underworld Breach combo

Infernal Tutor + Lion's Eye Diamond, three-mana, six-card Underworld Breach combo
Click to enlarge.

The card requirements in the tables included in this primer go down by one card if you allow yourself to exile your Lion’s Eye Diamond to the escape of Infernal Tutor—but this does mean that you have to hit another Lion’s Eye Diamond from your Brain Freeze and its copies.

  • In the case of a 2-mana, eight-card combo, you have enough mana to cast two Brain Freeze so your chances to hit another Lion’s Eye Diamond are closing in on 100% (there should be three cards left in your library, with the only fail-case being that two of them are the remaining Lion’s Eye Diamonds) assuming you have both Lion’s Eye Diamonds left in your deck.
  • It gets sketchier when you consider a 3-mana, five-cards combo since you only get to Brain Freeze yourself once; which comes in at 58.5% to hit another Lion’s Eye Diamond. These odds do increase if other spells are cast in the turn at a rate of approximately 7% for the first couple of additional storm copies.

You can also combo without having any of the cards available, except for a hellbent Infernal Tutor. This requires you to have a total of 6 mana, to cast your Infernal Tutor twice, and to cast an Underworld Breach; a situation which doesn’t come up too often. It gets easier when you have the combination of an Infernal Tutor and an Underworld Breach; how you win with those two cards and 4 mana is shown in this table.

Infernal Tutor + Underworld Breach, four-mana, six-card Underworld Breach combo

Infernal Tutor + Underworld Breach, four-mana, six-card Underworld Breach combo
Click to enlarge.

Basic combo tips:

  • Remember that casting a Force of Will by exiling a card from your hand reduces the available cards for the combo by one.
  • In specific situation you can pass without playing a creature and keep that card in your hand if you need one more card for your combo, though it’s generally not recommended to do so.
  • Every Lion’s Eye Diamond beyond the first reduces the required number of cards by three.
  • Naturally drawing Brain Freeze also reduces the set-up requirements by three cards, as you can skip getting black mana out of your Lion’s Eye Diamond for the escape on Infernal Tutor.
  • Having an Underworld Breach in hand doesn’t generally help the full combo, unless you have all three of the non-Infernal-Tutor pieces. But having Underworld Breach in hand can help with a Force of Will protected combo sequence.

The Combo: Interaction

In this part of the primer I’ll go into some of the ways you can combo through interaction your opponent can have, or how you can keep up interaction while playing out your Underworld Breach combo turn. As a general guideline, you should recognize that this deck is better suited to finding a spot where your opponent doesn’t or is unlikely to have interaction for your combo. As the set-up requirement to continue through interaction can be vast, and it can be challenging to play out.

Enchantment destruction

One of the identifying factors of the Underworld Breach combo is that it’s weak to enchantment removal on Underworld Breach, in addition to the card types typical combo decks are vulnerable to. It’s also not the easiest to play around.

As with other interaction, you should ask yourself what you should achieve to get around losing your Underworld Breach. Let’s assume you’re dealing with Abrupt Decay, as you can’t interact with that on the stack. To play around Abrupt Decay, you should give yourself the option to get a second Underworld Breach into play.

Abrupt Decay

With the basic Infernal Tutor + Lion’s Eye Diamond combo, the required start-up cost is a whopping 5 mana, in addition to the Lion’s Eye Diamond. This is because you will have to cast two Infernal Tutors, both getting an Underworld Breach you want to get onto the battlefield.

Infernal Tutor + Lion’s Eye Diamond, 5 mana, 12-card Underworld Breach combo vs. Enchantment destruction

Infernal Tutor + Lion's Eye Diamond, 5 mana, 12-card Underworld Breach combo vs. Enchantment destruction
Click to enlarge.

What helps with the starting requirements for playing around enchantment removal is having additional starting pieces. Having an Underworld Breach in your opening hand cuts 2 mana off the combo, and having a second Lion’s Eye Diamond means you have all the mana you need to get your second Breach and cast it too.

Alternatively, if you only have 3 starting mana, you can cast Infernal Tutor after your Underworld Breach resolves; getting you another Underworld Breach. At this point, if your opponent doesn’t respond you get to continue your combo by escaping Lion’s Eye Diamond. If your opponent casts Abrupt Decay on your first Underworld Breach, you pass the turn and start your combo with the second Underworld Breach on your following turn. This can be a good strategy in general, if you don’t know what to play around but do have enough cards in your graveyard.

Against an effect that returns your Underworld Breach to your hand, such as an opposing Petty Theft, you can simply make sure to float an additional 2 red mana throughout your combo turn. The most important part here is that you make sure to insulate yourselves from a bounce spell turning off the hellbent of your escaped Infernal Tutor. A well-versed opponent can pick their spot optimally, so plan accordingly when you suspect a bounce spell.

Targeted graveyard interaction

Targeted graveyard interaction, such as Surgical Extraction, is in an interesting spot against Grixis Breach Delver. While you can get blown out by it when you’re not respecting it, it’s also really easy to play around with minimal resources.

Surgical Extraction - Buy-a-Box Promo

By using the escape mechanic on other instants you have in your graveyard, you can exile a card that is targeted by Surgical Extraction as a cost, making sure other copies of the target are safe from its exile effect. This doesn’t always work as you want to for a card like Brain Freeze however, as you only have one copy in your deck. This makes it important to try and have up enough mana to cast Brain Freeze whenever it’s in your graveyard and you expect your opponent to have this kind of interaction.

In practice, this means that both for the storm count for the first Brain Freeze, as well as to play around an exile effect, it’s typically correct to cast Lion’s Eye Diamond an additional time before getting your Brain Freeze out of your deck. Watch out for exposing your Infernal Tutor if you still need that, though.

Taxing effects

There are two ways to combo through a taxing effect like Thalia, Guardian of Thraben, either by searching for a Lightning Bolt or other removal mid-combo, or by executing the combo through the taxing effect. In order to keep it general for taxing effect, and to account for ways your opponent has to protect their Thalia, I’ll detail the requirements to combo through the taxing effect in the following table.

Infernal Tutor + Lion’s Eye Diamond (in play), 4 mana, twelve-card Underworld Breach combo vs. Sphere of Resistance

Infernal Tutor + Lion's Eye Diamond (in play), 4 mana, twelve-card Underworld Breach combo vs. Sphere of Resistance
Click to enlarge.

After resolving the last part of this sequence, you have 3 mana from your Lion’s Eye Diamond and can use that mana to win by casting a couple of Brain Freezes targeting the opponent. Make sure not to drop to zero mana when casting anything but a Lion’s Eye Diamond, as it’ll shut you off of casting further spells.

Note that this specific table assumes that your first Lion’s Eye Diamond is already in play, add 1 mana to the start of the combo when you have to play your Lion’s Eye Diamond out as well. More reasons to play out early Lion’s Eye Diamond (or not) are discussed in the fair/alternative uses for Lion’s Eye Diamond. Any additional mana or combo pieces significantly reduce the number of cards you need to start with, as each card you have to Infernal Tutor for costs you a lot of mana and cards when you’re getting taxed on each of them.

Protection from Brain Freeze

There are a handful of cards that prevent you from killing your opponent by milling their entire deck with Brain Freeze copies, which is the most natural way to win the game and also gains information about your opponent’s exact deck configuration. Before sideboarding, you have access to Lightning Bolt, which is enough to kill your opponent from most life totals, mitigating this issue.


Emrakul, the Aeons TornVeil of Summer

There are two basic ways to approach this. If you keep a single Lightning Bolt in your deck when sideboarding, you keep this damage-based win condition as a clean win condition. Alternatively, you have the option to accept that you’re not winning the game on the spot with your combo, but are instead forcing your opponent to discard their hand (not against Veil of Summer), building a lethal board-state for the following turn, and sculpting your hand such that you have one or more pieces of countermagic open.

Lightning Bolt

This specifically comes up in combo matchups where your Lightning Bolts may not have a meaningful impact on the game when you draw it. Depending on the matchup the debate is whether or not you want to keep a single Lightning Bolt in your deck for games 2 and 3, against a deck like Blue/Green Show & Tell. I’ve leaned on the side of keeping one Lightning Bolt in the deck, as combo decks might sneak in a creature or two (e.g. Arcane Artisan, Xantid Swarm, or Monastery Mentor) in their post-sideboard games; and it’s rough to lose a game after not committing a single slot in your deck to win on the spot.

Note that losing access to your Lightning Bolts could also come up maindeck, such as against a Chalice of the Void on X=1. But you have a Brazen Borrower in your deck, and get to escape Petty Theft with Underworld Breach to get rid of the Chalice of the Void.

Brazen Borrower

Brazen Borrower // Petty Theft

Brazen Borrower is one of the new cards that sees play in basically all Delver shells these days. As a common two-of, it helps the Delver decks answer troublesome permanents they’d often have trouble winning through, such as a big creature, Chalice of the Void, or Batterskull. Which means that you’d look to include it for the Delver half of the strategy in the first place.

Where it shines though is that is allows you to threaten your combo post-board through permanents that are locking it out, such as Leyline of the Void, without adding one-dimensional answers. This means that, while you can partly pivot away from your combo to lessen the impact of these lock-out permanents, you don’t let your opponent sit behind a single piece worry-free. It’s also important to note that you get to escape the Petty Theft side of this card with Underworld Breach, to return an essential permanent to your opponent’s hand as you go through your deck (Brazen Borrower would then go to exile on an Adventure when Petty Theft resolves, like normal).

The combination of its uses as a good fair card and a bounce spell to make way for your combo makes Brazen Borrower one of the key cards for the deck.

Keeping up countermagic

While it’s hard to find ways to keep up countermagic while also wanting to get Infernal Tutor to be hellbent, it is possible if you naturally find one of your Underworld Breaches. You’re often able to cast the Underworld Breach with a Lion’s Eye Diamond in play, and a Force of Will in your hand, along with a blue card. This allows you to keep your countermagic open until the Underworld Breach hits the battlefield, at which point you’re safe to sacrifice your Lion’s Eye Diamond and discard your countermagic. From this point on you can keep up enough mana to escape your countermagic out of the graveyard and regularly escape your Lion’s Eye Diamond an additional time.

The discord between using countermagic as protection and Infernal Tutor as your enabler is a tough one, but both cards have been strong enough that I wouldn’t cut either. It does, however, mean that when doubting about what the correct cuts are post-sideboarding, it’s often correct to trim down on the number of Force of Wills.

Force of Will

Note that you’re unable to cast Force of Will by exiling a blue card from your hand when you’re using the escape mechanic, as both are alternate costs and only the escape cost lets you cast it from the graveyard. Force of Negation is a different story, as it’s impossible to use it as protection without having a significant amount of surplus mana. The Force of Negation therefore specifically comes in when you expect to have the reactive role in post-sideboard games.


The most effective way to punish players when they’re spending resources to shut out your combo, or to keep up interaction, is to beat them down. The Underworld Breach combo is strong and fast enough that it demands many decks have a plan for it. Due to your Brazen Borrowers, discard spells, and countermagic, they can’t go too light on it either. Which means that this opens up a window for your beatdown plan.

At the end of the day, there are few feelings in Magic better than opening a game on a Delver of Secrets—especially after your opponent committed two Leyline of the Voids onto the battlefield.

Fair Magic: Alternative Uses and Synergies

With a deck set up as Grixis Underworld Breach is, one of the key things is to discover how you can make the pieces of your disparate strategies work for the other. Just as Brazen Borrower is one of your creatures that supports your combo plan, you mostly focus on making your Underworld Breach combo pieces work for your fair Delver strategy.

Underworld Breach

Underworld Breach

Underworld Breach is the most powerful of the dedicated combo cards when it comes to its fair uses. It functions like a Snapcaster Mage without the creature, but in exchange you get to cast all the spells any number of times as long as you pay the mana. This means that it’s often possible to play Underworld Breach with access to 4 mana as a semi-Kolaghan’s-Command for any two combinations of killing a creature, forcing your opponent to discard, or casting a Delver of Secrets from your graveyard.

Access to Thought Scour also means that you get to convert each blue mana you have available to a card, and get more options into the graveyard. The most common use is that Underworld Breach combines with Lion’s Eye Diamond in spots where you can’t necessarily win the game, but instead get to see and draw a lot of extra cards. Underworld Breach plus Thought Scour essentially turns each Lion’s Eye Diamond you can cast into a zero-mana Ancestral Recall. If the graveyard is decently filled, you can also turn any red mana you produce after casting the Underworld Breach into a Lightning Bolt, giving you the option to finish off an opponent from 9 or 6 life.

Note that when you’re in a dire spot, Underworld Breach can often be a last-ditch effort to win the game by casting a card draw spell (like Ponder) out of the graveyard and hoping to hit a Lion’s Eye Diamond.

Infernal Tutor

Infernal Tutor

Infernal Tutor has a very clear primary use for your fair strategy, and that’s to get any card out of your deck when you are hellbent. But in a deck with Force of Wills and other situational cards, it doesn’t come up too much. In an earlier version I also had a Bedlam Reveler in the deck to enhance the power of the hellbent topdeck Infernal tutor. Through playing, we found that it came up too sparsely, and cut the Bedlam Reveler for other cards.

What does come up occasionally in game 1, but especially post-board, is that you have your Infernal Tutor and Lion’s Eye Diamond but can’t combo off. These are scenarios where your one-ofs can do some heavy lifting. Some examples include getting a Plague Engineer against an early Empty the Warrens, or a Karakas when you’re facing down an early Marit Lage. Sometimes you just need to cast a discard spell to win the game safely; don’t be afraid to discard your hand to get the card you think is going to win you the game, even if that’s just a Thoughtseize.

The most frequent use of a non-combo Infernal Tutor is to double up on an important card in your hand. Against combo you can often tutor up an additional Force of Will, but there are also spots where you get a second Lightning Bolt to clear the board or finish off your opponent. You also shouldn’t be afraid to just double-up on a Ponder, if that’s what you have.

Lion’s Eye Diamond

Lion's Eye Diamond

Lion’s Eye Diamond is one of the worst cards you can find if you don’t have access to either Infernal Tutor or Underworld Breach. That doesn’t mean it is useless though, and I’ve won many a game on non-intuitive uses of the card. I would not typically run out a Lion’s Eye Diamond onto the battlefield, as that gives the opponent a lot of information, but keep an eye out for spots where you might need the mana at an unexpected time.

For example, you can use the 3 mana from Lion’s Eye Diamond to cast a Brazen Borrower from your exile zone, which can give you an unexpected tempo boost in the first couple of turns. One scenario where this has been especially strong is against a deck like Eldrazi, where you get to curve your Delver of Secrets into a bounce spell on something like a Thought-Knot Seer as well as cast the Brazen Borrower on your second turn—turning up the heat on your opponent.

Another very strong use is to power out an early escaped Kroxa, Titan of Death’s Hunger. By using Lion’s Eye Diamond to fuel the graveyard as well as produce the required mana, you can escape your Kroxa on turn 2, which some decks can’t come back from.

Even later than turn 2, you can sometimes use some of your mana to cast other spells, and then use a remaining Lion’s Eye Diamond to escape out your Kroxa. Note that this requires 2 mana of the same color in addition to the mana from Lion’s Eye Diamond, which can make it correct to get out an early Badlands, and keep this line op play open.

The weakest of these interactions, but the freest to play with in the typical game, is its interaction with Cling to Dust. By having a Lion’s Eye Diamond in play, it allows you to turn your single piece of graveyard interaction into a second one. Or draw an extra card where you’d otherwise have nothing to do. This also lets you have graveyard hate against a deck like B/R Reanimator through their discard spells—where you’d otherwise lose your ability to interact with them.

Brain Freeze

Brain Freeze

Brain Freeze is by far the least useful card outside of your combo, as it’s typically only used to target yourself to fuel your graveyard when you’re looking to find some action, to hit a Kroxa or to get a Lion’s Eye Diamond in the ‘yard, on a turn where one or two other spells are already cast.

Another corner-case use for it is to go for a Brain Freeze storm kill, putting all or most of your opponent’s deck into their graveyard. While it doesn’t come up often, it is a very important alternative plan to keep in mind. It’s often a way to win games you didn’t have any other chance in.

Some examples:

  • My teammate won the last games of the finals on the Dutch Open Series by Brain Freezing their Five-Color Control opponent, when they cast enough other spells to mill their opponent for 27 cards. They were staring down a Rest in Peace and a lethal army of Elks at the time.
  • An U/W Miracles opponent had me locked under an early Counterbalance and Back to Basics, only to have me eventually Brain Freeze them out by firing off all my spells in a single turn.

An advantage Brain Freeze does have is that it’s blue, which means you can use it for the alternative casting cost on Force of Will. But keep in mind that you only have a single Brain Freeze in your deck, and exiling it means that you lose your ability to win with your Underworld Breach combo. I’d recommend to consider your options well when making this play.

Thought Scour

Thought Scour

While Thought Scour isn’t necessarily a piece of your combo package, it is a card that you wouldn’t naturally play in a Grixis Delver deck. Its main reason for inclusion is simply to fuel your combo. You both have a minimum number of cards you need access to, as previously addressed, but you also get more options with your combo for each card you have access to in your graveyard.

Besides fueling your Underworld Breach, Thought Scour also helps out when you’re not looking to go into a certain part of your game plan or don’t mind a certain card being in your graveyard. Here you can look for spots to get some additional value out of Thought Scour. Examples on your own side of the board are when combined with Brainstorm, or when you know the top of your library due to Delver of Secrets.

For more direct value, keep in mind that, while you normally want to target yourself with the Thought Scour, it can be important to keep it up in order to disrupt the opponent. Some currently relevant applications of this are against Enlightened Tutor, Mystic Sanctuary, Counterbalance, or Terminus (before your opponent would draw and reveal it).

While Thought Scour is very important to fuel your early kills, especially through mulligans—it’s significantly weaker than Ponder. To compensate, you’re currently running a three-and-three split of these card draw spells.

Fair Magic: Powerful Bullets

In addition to having a nice Underworld Breach combo in the Delver shell—you also have some other interesting card inclusions. Here are those cards, and why I recommend having them in this strategy.

Kroxa, Titan of Death’s Hunger, et al.

Kroxa, Titan of Death's Hunger

The one-of Kroxa is a weird look in this deck, as it’s not a typical Delver inclusion nor does it play a particular role in the Underworld Breach combo. That being said, the two new Titans (Uro and Kroxa) are both on the rise in Legacy, as people are slowly figuring just how strong they are. While Uro, Titan of Nature’s Wrath definitely is the stronger of the two, Kroxa shouldn’t be underestimated.

An “advantage” your Delver strategy has over established Delver builds is that you lack both Daze and Wasteland. The exclusion of those cards allows you to play bigger and more color-intensive cards. Your disparate strategic plans also put a higher importance on including cards that can win a game on their own. Kroxa is the most powerful of the three cards that are in the deck with that thought in mind, with the other cards being True-Name Nemesis and Plague Engineer.


Plague EngineerTrue-Name Nemesis

On power level, I’d love to include another Kroxa in this deck (over the True-Name Nemesis for example), but you have to keep the reliance on your graveyard to a minimum, as you don’t want both of your plans getting significantly impacted by the same sideboard cards.



When discussing the deck, we found that there was a pull to add an additional mana source to the deck, while we largely had covered the color requirements already. This meant that we could look for a utility land. Between Marit Lage, Thalia, Emry, Sai, Urza, and many other popular legendary creatures, Karakas is a card I already like to have access to in all my Delver sideboards. Because we wanted another land for the deck, we moved the Karakas to the main deck. This also allows you to Infernal Tutor for it in dire situations.

An important interaction that comes up is the interaction between Karakas and Kroxa, Titan of Death’s Hunger. By returning Kroxa to your hand before it gets sacrificed to its own enters-the-battlefield ability, you get to strip your opponent’s cards from their hand—and even deal 3 damage per cast when they’re out of cards to discard.

Note that it’s typically correct to stack the Kroxa triggers such that your opponent discards their card first, before Kroxa getting sacrificed. To play around graveyard hate they might have to discard or use on a different card if you stack it correctly. The same goes for stacking it like that when you have Karakas, such that your opponent has to discard or use their removal (e.g. Swords to Plowshares) before you activate your Karakas on your own Kroxa.

It can be awkward that Karakas doesn’t pay for the BBRR escape cost on Kroxa, but the fact that it works so well with the front end of the card has more than made up for it.

The Friends We Lost Along the Way

This primer would not be complete without addressing the cards that got left by the wayside when you needed slot in your Delver shell, so here’s just that.

Daze & Wasteland



The holy duo of Legacy tempo, and the reason Delver of Secrets sees play in the format. Giving up these tools is rough, and requires a strong reason. One of the major reasons for the exclusion of Daze is that the card is very bad with Infernal Tutor, as it requires you to return lands to your hand where the Infernal Tutor is asking you to empty it. You’re also looking to make your land drops such that you get into spots where you have enough mana to play around your opponent’s interaction.

Wasteland is an incredibly powerful card, but without Daze, and with the increased mana requirements of this deck compared to typical Delver decks, it’s been my decision to leave it out of this build. There’s an option to restructure the deck such that Daze or Wasteland can get back into the deck, but we’re tight on spots as is—and the current configuration has felt good without them.

While this deck might get some bonus value from your opponents not recognizing your lack of access to these effects, it’s good to note that you can expect other Delver decks to remain more popular. And people needing to respect these cards until they have strong confirmation that you’re on the Breach Delver version of the deck, means that you can continue to gain value from these kindred archetypes.

Dreadhorde Arcanist

Dreadhorde Arcanist

It’s my educated opinion that Dreadhorde Arcanist is the best creature that current established Delver decks have access to. Thus, it is with no small amount of pain in my heart that I am playing a Delver deck without the Zombie Wizard in it. This is a calculated choice, as I do feel that the power of the Underworld Breach combo is worth the exclusion of Dreadhorde Arcanist. One of the important factors for not having both the Underworld Breach and Dreadhorde Arcanist plans in the deck simultaneously is that you want your non-Breach cards to be able to lock up a game when you cannot close it out with the Breach plan. While Dreadhorde Arcanist is very powerful, and attacking with it usually leads getting significantly ahead in a game—it typically needs help to actually close a game out. The combination of that thought, combined with the pressure it would put on having certain cards in your graveyard, makes me believe its exclusion is justified.

There is definitely room to explore the inclusion of a few Dreadhorde Arcanists in this deck, over other graveyard-dependent spells like Kroxa, Titan of Death’s Hunger and Cling to Dust. Though its inclusion would increase your reliance on the graveyard, which weakens you to cards like Leyline of the Void.

Closing Thoughts

Grixis Breach Delver truly is a blast to play; and I’m looking forward to what happens to a deck like this when other minds and the community get their run with it. All I hope is that this article can inspire people to give it its fair chance.

Fighting against the Grixis Breach Delver strategy:

It can struggle against strong proactive decks with cards that are good against both plans, such as aggressive Eldrazi decks with their Thought-Knot Seers and Chalice of the Voids. And while most control decks’ answers only line up with either of the strategic parts of the deck, Counterbalance is a card that can interact favorably with both. Because you don’t play any basic land and trimmed Dazes, you’re vulnerable to nonbasic lock pieces such as Blood Moon or Back to Basics. Keep an eye out for a metagame that’s rife with these effects, as Grixis Breach Delver may not be optimal there.

Don’t hesitate to let me know your experiences with or questions about the deck list—and I’m looking forward to exploring the archetype with the rest of the community, as there’s still a lot to test and improve on.

Thank you for reading, as I’ll leave you with this philosophical postulate: 

“Lion’s Eye Diamond is a powerful way to sacrifice card-quantity for an immediate mana advantage. Therefore, Lion’s Eye Diamond is a tempo card.”

Lion's Eye Diamond Anime Meme

Shout-out to my teammate Kasper Euser for not only winning the Dutch Open Series with Grixis Breach Delver, but also for helping on the deck and for proofreading this primer.


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