Since it’s announcement Pioneer has been flooded with wild decks. 

It’s a new format, why not brew? But all of them have been quickly ousted by the format’s premier aggressive decks.

So when Dimir Inverter started picking up popularity while Piotr “Kanister” Glogowski tuned the initial builds, I simply swapped a couple cards around in the Izzet Ensoul sideboard and got back in the queue. But then when I played the matchup again, I found that my answers just weren’t good enough.

[Card]Mystical Dispute[/Card] whiffed against Inverter itself, and was too soft to stop a [Card]Thassa’s Oracle[/Card]. [Card]Metallic Rebuke[/Card] and [Card]Disdainful Stroke[/Card] were too hard to hold up while still exerting enough pressure to kill them before discard spells picked my hand apart. No card I tried was a meaningful improvement over submitting my maindeck again.

I turned to Mono-Red, then Azorius Control, then Spirits. Everywhere the same pattern emerged — the ceiling on the Inverter deck was so high that each matchup was minimum 50/50 and if they were prepared for you, or played well, or drew well you likely didn’t stand a chance. There was just no beating it consistently. I’ve been jamming it ever since, and the deck is both excellent and incredibly rewarding to strong play and a thorough understanding of how to tune it from week to week.

To start with, here’s the list I would recommend:

[Deck Title= Dimir Inverter – Baker Neenan]
[Creatures]
4 Inverter of Truth
4 Thassa’s Oracle
[/Creatures]
[Spells]
4 Jace, Wielder of Mysteries
4 Dig Through Time
4 Fatal Push
1 Hero’s Downfall
1 Mystical Dispute
1 Omen of the Sea
4 Opt
3 Thought Erasure
4 Thoughtseize
[/Spells]
[Lands]
2 Choked Estuary
4 Drowned Catacomb
3 Fabled Passage
2 Fetid Pools
1 Ipnu Rivulet
6 Island
3 Swamp
1 Urborg, Tomb of Yawgmoth
4 Watery Grave
[/Lands]
[Sideboard]
1 Aether Gust
1 Cry of the Carnarium
2 Damping Sphere
1 Disfigure
2 Kalitas, Traitor of Ghet
2 Leyline of the Void
3 Mystical Dispute
2 Narset, Parter of Veils
1 Noxious Grasp
[/Sideboard]
[/Deck]

Since my love affair with this deck started, I’ve managed to have quite a bit of success with it. I Top 4’d the Trios Open in Richmond the weekend the deck took off and then managed a 12-3 finish at GP Phoenix.

Did poorly in the PT but rallied with 12-3 in the GP for 19th with Inverter. Deck is a deeeelight

— Baker “VTCLA” Neenan (@VTCLA1) February 10, 2020

It differs slightly from the list I registered at Grand Prix Phoenix, which had a second [Card]Hero’s Downfall[/Card] and a [Card]Jace, Vryn’s Prodigy[/Card] in the sideboard over the second Narset and second Leyline. 

There’s a balance in deckbuilding between playing cards with a flat power level that are generically useful across most matchups and cards that are more narrow but higher impact. While there are a lot of factors that go into each decision in this balancing act, the most important one by far is how much “wiggle room” you have in games you win. Every deck can run away with a game, but midrange decks are more prone to scraping across the finish line, while decks with a two-card combo can lean on that power level to win  while sitting on several dead cards. In the case of Inverter, whether you want to play a midrange game or a combo game depends on the matchup. The more disruption the opposing deck has, the more crucial it is that every card in our deck be live so that we can flip the script and scrape out wins with [Card]Dig Through Time[/Card] instead of just buying time to set up a combo.

After this past weekend in Phoenix, it’s this very axis — combo versus midrange — that the entire Pioneer format balances on.

Lotus Breach effectively falls into the latter category, since they win the combo race pretty easily when they aren’t heavily disrupted. Against them it’s crucial that disruption pieces reliably trade for a card and be capable of doing so proactively because counter-magic can easily be overloaded on a combo turn fueled by extra mana from [Card]Lotus Field[/Card]. This is also true of the Inverter for different reasons, namely that reactive answers can be susceptible to discard spells which can then force through a threat.

The large amount of discard tends to strip away a lot of the action from each player’s hand so the potential tempo gain is less important. For this reason, I cut my copies of [Card]Censor[/Card] and want to play at least three [Card]Thought Erasure[/Card]. The first [Card]Omen of the Sea[/Card] over the fourth [Card]Thought Erasure[/Card] is a nod to increasing the quality of our average top-deck, and finding both halves of the combo by turn four as often as possible against aggressive decks. It also has a lot of additional utility, turning on [Card]Fatal Push[/Card], letting you win the game with an empty library in response to removal on Jace, and most crucially adding a devotion so Oracle kills through removal with one card in your deck. That sounds like a narrow scenario but it actually comes up constantly when you [Card]Dig Through Time[/Card] end of turn to set up a one-turn-kill with Inverter and Oracle on turn six.

Another concept that played into how I want to built Inverter is the idea that negative tempo plays have diminishing returns. When you play one discard spell you fall a little bit behind, but it’s easy enough to catch back up due to the resulting shift in hand quality. Each additional mana you fail to spend impacting the board exacerbates the issue though, and if you spend your first three turns on card selection (either cantrips or discard) you’re likely to die to any opponent who just played a threat in those turns before you can stabilize.

With this many discard spells, it’s crucial that we be able to plan for these positions, which is one of the reasons I played the full four [Card]Thassa’s Oracle[/Card] despite the card being somewhat mediocre and getting boarded out a lot. It’s just too important to have a higher density of cheap plays that can shut down opposing one-drops effectively.

Interaction that never plays well from behind like [Card]Supreme Will[/Card] or [Card]Censor[/Card] I want to avoid entirely. The first Downfall is a necessity for killing [Card]Gideon of the Trials[/Card] and Jaces in the mirror, but playing more just gets you killed by one-drops. Instead I played a [Card]Mystical Dispute[/Card] maindeck for similar reasons to what I talked about earlier; the importance of drawing a dead card against [Card]Mono-Red[/Card] is fairly low due to the nature of the matchup whereas against Spirits or [Card]Lotus Field[/Card] it’s often game-changing to have an efficient piece of interaction that can swing the race while trying to close the game after the initial wave of discard. It’s also just insane in the mirror, particularly as an extra way to stop Jace from resolving in game one.

A quick aside on the manabase — [Card]Ipnu Rivulet[/Card] and [Card]Urborg, Tomb of Yawgmoth[/Card] are both extremely powerful lands to have access to, the former for the mirror and accelerating kills with a large deck and the latter for fixing your mana and turning [Card]Fabled Passage[/Card] into a real mana source post-Inverter.

The cost is a slight hit on the quantity of Swamps and Islands to turn on [Card]Choked Estuary[/Card] and [Card]Drowned Catacomb[/Card]. [Card]Fetid Pools[/Card] is the easiest way to reconcile the difference, so I played two and took advantage of the extra cycling power to make room for a 26th land. 

While we’re here, let’s talk about how to use Rivulet in the mirrors. First, always try to sandbag it as long as possible if your opponent hasn’t seen it off a [Card]Thoughtseize[/Card] yet to bait them into going for a combo setup thinking it’s safe. Eventually you need it in play to stop a one-turn-kill with Oracle that bypasses the draw step, so once that becomes a real possibility, get it in play if you’re going to have the mana up for it. Generally the way to beat an opposing Rivulet involves sticking a [Card]Jace, Wielder of Mysteries[/Card] and either comboing with no fear or just grinding them out of resources.

Constructing a sideboard each week is one of the more difficult aspects of Magic, but I’ll share with you how I arrived at what I did for the Grand Prix and what I would do going forward and hopefully that should give you some insight for how to adjust going forward. First off is the non-negotiable four [Card]Mystical Dispute[/Card] in the 75. The card is frankly just broken in blue mirrors, and the ability to narrow the focus of the game to a combo kill that forces narrow windows of interaction limits the capacity of it to go dead late in the game.

Aside from these, there are very few cards that are actually much good in the mirror. [Card]Pack Rat[/Card] is just awful — it masquerades as a two-drop, but really takes at least eight mana to become a meaningful threat, and while you’re doing that your opponent will easily bury you in card draw and kill you with the combo even if your [Card]Pack Rat[/Card] does come down early and stick.

[Card]Jace Vryn’s Prodigy[/Card] is a far more effective two drop mix-up threat, but you can only afford so much durdly card draw in your sideboard and JVP suffers from splash damage against opponents who board in [Card]Rest in Peace[/Card] or [Card]Leyline of the Void[/Card], so we’d rather turn elsewhere. The card I’ve found most effective is [Card]Narset, Parter of Veils[/Card], tech I shamelessly ripped from Oliver Tomajko after he beat me with it in the Pro Tour day one. A three mana blue card is pushing it in a world dominated by [Card]Mystical Dispute[/Card], but drawing extra cards (literally and figuratively) is so crucial in the mirror and this is by far the best rate available for winning that battle. I played one JVP one Narset in the GP and would register two Narset now.

Narset also serves as solid splash damage against Lotus Breach. In that matchup, there’s a strong limit to how much can be accomplished with single pieces of one-for-one interaction. Their top decks are so strong between [Card]Underworld Breach[/Card], [Card]Fae of Wishes[/Card], [Card]Pore Over the Pages[/Card], [Card]Dig Through Time[/Card], [Card]Expansion // Explosion[/Card] and sideboard cards like [Card]Niv-Mizzet, Parun[/Card], and cantrips to find them.

Trying to [Card]Thoughtseize[/Card] them out of threats is just not a winning battle. Counterspells help some, but the mana generation from [Card]Lotus Field[/Card] and [Card]Thespian’s Stage[/Card] allows them to play through [Card]Mystical Dispute[/Card] too easily (you should basically fire these off at every possible opportunity to trade for a card because they don’t really get better). You could play some [Card]Negate[/Card] on top of the Disputes, but they still avoid getting bottle-necked on mana so easily that they can play through it without too much difficulty and it’s not that applicable in other matchups anyway.

[Card]Aether Gust[/Card], particularly in combination with Jace clearing the top of their deck, can delay Breach and Niv-Mizzet or set them back a turn by hitting an early [Card]Sylvan Scrying[/Card], but is too narrow to really want more than one. Really the answer is just stacking lock pieces to disrupt their functionality wholesale. Narset only really kills Pore, but it also draws two cards and can help you rebuild from a [Card]Thought Distortion[/Card] by being a delayed card draw spell so it’s still quite good. [Card]Damping Sphere[/Card] is the gold standard since it shuts off their mana functionality and ability to cantrip easily as well as their ability to combo, but it’s only good against this deck. [Card]Leyline of the Void[/Card] doubles as effective hate for the Sultai decks, both Inverter and typical Delirium variants. Two of each is a nice balance that helps us cover our bases while still ensuring we have sufficient hate to reliably win post-board games in a matchup with a pretty poor game one.

As mentioned earlier, against Mono-Red and Mono-Black the combo kill allows us to iron out the wrinkles of how we answer every card they play, whether it’s red’s burn or black’s recursion, and simply buy time to set up a kill. Accordingly, we want to lean into the same gameplan, leaving in some discard and using it to clear the path for Kalitas to take over the game as another way to invalidate everything cheap that snuck through in the early turns at once. [Card]Enter the God-Eternals[/Card] has a higher floor into a bunch of removal that hits them, but the extra mana cost and necessity of a target against red are crucial downsides and it doesn’t close the game nearly as quickly.

[Card]Aether Gust[/Card] and [Card]Cry of the Carnarium[/Card] are excellent against Red and Black respectively, so one of each is pretty justifiable. [Card]Legion’s End[/Card] made it’s way into sideboards when Ensoul and Mono-Black were the top aggro decks to respect, but with Spirits and Mono-Red now the dominant aggressive decks the utility of End is no longer worth the inefficiency, and being a Sorcery is actively a huge liability against [Card]Mutavault[/Card] and a wave of flash and haste creatures, especially [Card]Rattlechains[/Card]. [Card]Disfigure[/Card] is a better replacement as an extra cheap removal spell.

The spirits matchup is largely defined by their ability to setup blowouts when you’re forced to play the game on their terms because your options are limited at dealing with their early pressure. The simple way to counteract this is just to overload on hyperefficient interaction to beat them at their own game and then bury them with Dig Through Time. You normally want to spend the early game picking off their cheap creatures before they can untap and get up to their usual flash tricks so you can buy time to play card draw with Dispute backup. Sweepers like Languish and Witch’s Vengeance are appealing and can generate insane blowouts, but also are hard to set up since they play counter to that baseline game plan, so when you draw them in the midgame they will often force you to take damage from a flash threat before being cashed in for a one for one. Gideon of the Trials is probably uncastable in their deck, but that hasn’t always stopped people before so you probably need some amount of removal that hits it just in case. [Card]Noxious Grasp[/Card] is somewhat narrow, but the mana discrepancy between it and [Card]Hero’s Downfall[/Card] is too important so we’d rather have that here.

Ensoul largely plays similarly to Spirits post-board, as you can expect them to board in a pile of soft permission, but they’re much worse at actually enacting this gameplan due to their threat light nature. It’s a lot safer to leave a threat around if it’s only attacking for one since there’s no snowballing blowout potential for killing it later the way there is with spirits. If Ensoul sees a resurgence in an attempt to prey on Lotus Breach we can make room for an [Card]Infernal Reckoning[/Card] somewhere, but I’ll believe it when I see it and the matchup isn’t really terrifying as is.

Sultai Delirium has a hard time disrupting your combo in a meaningful time-frame outside of attempting to cheese you with hate cards like [Card]Leyline of the Void[/Card] or [Card]Unmoored Ego[/Card]. Our own Leylines are far more damaging to their gameplan, eliminating almost entirely their ability to generate advantage in the midgame which should provide you plenty of time to grind them out with planeswalkers. [Card]Mystical Dispute[/Card] actually ends up being quite poor here as they fight us mostly with discard and removal rather than counter-magic, so we’d rather just leave in some removal to answer [Card]Tireless Tracker[/Card].

Mono-White Devotion is another matchup where Kalitas shines that [Card]Enter the God-Eternals[/Card] wouldn’t perform nearly as well in. Their capacity to answer the combo is limited to weird hate cards like [Card]Gideon of the Trials[/Card] and [Card]Gideon’s Intervention[/Card], both of which can be invalidated pretty easily by simply winning the board. The ability to brick wall their cheap creatures also allows you to sit on removal to stop a Ballista kill, while the continued presence of a lifelink threat and ability to chump and sacrifice tokens is crucial to beating a Heliod that’s online.

On when to cast Inverter of Truths:

The short answer here is “as soon as possible.”

If you’re holding off to try and ensure the Inverter resolves in the first place, by all means wait, and there’s definitely a lot of context to inform things here. But generally you shouldn’t wait to shrink your graveyard first, or get some perfect one-turn-kill setup unless necessary (namely in the face of [Card]Ipnu Rivulet[/Card] or [Card]Tome Scour[/Card]), and sometimes you shouldn’t even wait for a combo piece. 6/6 fliers are more than capable of being their own win condition, and often your opponent is put into a no win situation when you can leave yourself with enough turns to close the game with attack steps.

Two Inverters can be a “soft combo” along those lines, allowing you to cast a couple disruption spells then follow up with a second 6/6 that shuffles them back in. The main key is not to be afraid of some coin flips. Relinquishing all control over the game’s outcome to the order of the cards in your deck may feel unappealing, but it can often swing you from even or behind to a significant favourite.

On who to target with [Card]Jace, Wielder of Mysteries[/Card]:

Whenever you can mill a good card from your opponent, either because they scry’d to the top or because you [Card]Aether Gust[/Card]’d and they topped, you usually want to do that. Otherwise, the balancing act here is accounting for three things:

First, do you want your graveyard smaller so that you can kill quicker off an Inverter.

Second, do you want your graveyard larger so you can cast a [Card]Dig Through Time[/Card].

And third, what fuel are you giving your opponent by milling them? On balance, this means if your opponent is playing Uro, [Card]Underworld Breach[/Card] or [Card]Scrapheap Scrounger[/Card] you hardly ever mill them, and otherwise you try to stay as close to zero or six cards in yard as possible depending on how easily you can access Dig. In the mirror things get even more complicated since you have your opponent’s interests to consider as well, but since Dig is the default take off of discard spells anyway, you often end up targeting your opponent just to slow down their potential kill and speed up yours. 

More than any deck I’ve played, Inverter is built around constantly putting you in new situations, where the slightest difference — say, whether a [Card]Thoughtseize[/Card] or [Card]Thought Erasure[/Card] is in your graveyard — can fundamentally reshape how the game plays out after an Inverter resolves. This makes it both wildly re-playable and also extremely difficult to master, which is why it is rapidly rising to the top of my favorite decks I’ve ever played. So try to pick up what heuristics you can, but always be on the lookout for the little twists each game has to offer.

Sideboard Guide

VS Mirror:
-3 Fatal Push
-2 Thassa’s Oracle
+3 Mystical Dispute
+2 Narset, Parter of Veils

Oracle comes out a lot in matchups where we’re facing disruption and the body isn’t relevant, as it’s just not worth a card when we can’t reliably set up a combo. Leaving in a Push here to hedge against JVP and other mixup threats, as well as to kill random Inverters or occasionally protect Narset from an opposing Oracle.

VS Breach:
-4 Fatal Push
-2 Thassa’s Oracle
-1 Jace, Wielder of Mysteries
-1 Hero’s Downfall
-1 Inverter of Truths
+2 Damping Sphere
+2 Leyline of the Void
+2 Narset, Parter of Veils
+2 Mystical Dispute
+1 Aether Gust

Combo setups aren’t really fast enough to keep up so we shave them for disruption and plan to find missing pieces once we start casting [Card]Dig Through Time[/Card]. Mulligan any hand that doesn’t contain Sphere, Leyline, Narset and a discard spell, or multiple discard spells.

VS Mono Red:
-4 Thoughtseize
-1 Mystical Dispute
+1 Disfigure
+1 Aether Gust
+2 Kalitas, Traitor of Ghet
+1 Cry of the Carnarium

Whether to board in Cry or leave in the Dispute depends on the exact construction of the red deck. If they aren’t heavy on burn you can also leave in a [Card]Thoughtseize[/Card], particularly on the draw when the three drops can be difficult to line up against their draw effectively.

VS Bant Spirits:
-3 Thassa’s Oracle
-1 Jace, Wielder of Mysteries
-1 Hero’s Downfall
+3 Mystical Dispute
+1 Noxious Grasp
+1 Disfigure

If your opponent has [Card]Gideon of the Trials[/Card], leave in Downfall over a [Card]Thought Erasure[/Card]. If they have [Card]Rest in Peace[/Card], shave a [Card]Dig Through Time[/Card] for Downfall.

VS Sultai Delirium:
-3 Fatal Push
-1 Mystical Dispute
-2 Thassa’s Oracle
+2 Leyline of the Void
+2 Narset, Parter of Veils
+1 Noxious Grasp
+1 Aether Gust

VS Mono Black:
-2 Thoughtseize
-1 Thought Erasure
-1 Mystical Dispute
+1 Cry of the Carnarium
+2 Kalitas, Traitor of Ghet
+1 Disfigure

VS UW Control:
-4 Fatal Push
-2 Thassa’s Oracle
+3 Mystical Dispute
+2 Narset, Parter of Veils
+1 Noxious Grasp

VS 5C Niv-Mizzet:
-4 Fatal Push
-2 Thassa’s Oracle
-1 Inverter of Truths
+3 Mystical Dispute
+1 Aether Gust
+1 Noxious Grasp
+2 Narset, Parter of Veils

This matchup often comes down to you taking the control role once your opponent names [Card]Inverter of Truths[/Card] with [Card]Slaughter Games[/Card]. From there your plan is to stick a [Card]Jace, Wielder of Mysteries[/Card] and deck yourself the hard way by chaining card draw and milling yourself.