The Game Plan
This deck is an Ancient Tomb combo/midrange deck that is trying to play fairly powerful cards ahead of schedule. The primary plan is to combine Leyline of the Void with Helm of Obedience to mill your opponent's entire deck and win on the spot.
In the past, this deck had to rely on playing larger numbers of Helm of Obedience , which would otherwise do very little without a Leyline in play. However, with Beseech the Mirror , that isn't an issue anymore and this deck can have the best of both worlds. Outside of the combo, this deck plays a lot of powerful black cards, such as Orcish Bowmasters and Sheoldred, the Apocalypse that can easily take over a game by themselves. It backs all of this up with a robust discard suite and even utilizes Urza's Saga to attack opponents from a different direction.
Breaking Down the Deck List
4 Beseech the Mirror
In a format like Legacy, this card is unquestionably powerful. It's a perfect card to pair with Dark Ritual and it's not particularly difficult to find a target for bargain. The fact that it casts the card when you bargain is incredible and it makes this one of the best tutors the format has ever seen since you won't lose any mana to get a 4-drop.
This deck is chock full of powerful targets, and being able to range from assembling your combo to disrupting your opponent and everything in between is great. While there are a lot of potent ways to make use of this card in Storm decks, I think this is the most natural home for the deck since this deck plays a fair amount of pieces that can be disjointed at times.
A lot of cards printed for this archetype lately have been moving the needle on its metagame position, but I think Beseech is the most impactful card that has been printed for this deck in the past few years.
4 Orcish Bowmasters
At the moment, this is my vote for the most format-warping card in Legacy. It completely shifts what strategies are desirable and makes playing both cantrips and creatures a complicated endeavor. While Bowmasters has fully been adopted by a variety of blue decks, I think this is the place where it really shines.
It provides this deck with a key threat, disruption for creatures, and punishes cantrips, all of which can be done as early as turn 1. On top of that, this deck doesn't play cantrips, so opposing Bowmasters are far less annoying than they would otherwise be. Right now, I think this card is the face of Legacy and playing a deck that can maximize its potential is a great strategy by itself.
4 Leyline of the Void, 4 Dauthi Voidwalker
These effects are at the core of the strategy. There are a lot of decks in Legacy that depend on the graveyard, so having a way to completely shut down those strategies full-stop can be devastating. By itself, that would not be worth including a card like Leyline of the Void. However, pairing it with Helm of Obedience provides you with a quick and easy way to win the game, and that combination is certainly worth building around.
Dauthi Voidwalker doesn't impact the game on turn 0, but it provides the same effect, while also having the ability to significantly impact the game. It applies a meaningful amount of pressure to your opponent's life total and threatens to take one of their key cards, which greatly matters. Having access to 8 copies of the Leyline effect is key for the combo and it's a part of the reason this deck has seen some success recently.
1 Karn, the Great Creator , 1 Helm of Obedience , 1Ill-Gotten Gains , 1 Sheoldred, the Apocalypse
With Beseech the Mirror around, this deck gets to play a nice toolbox here. In the past, this deck had to rely on naturally drawing cards like Helm of Obedience and Sheoldred, the Apocalypse , which meant they had to play larger numbers of those cards. While those cards are quite good in the deck, being 4-drops that are only good in select situations leaves you liable to drawing them at inopportune times.
With Beseech, you don't need more than a single copy, which significantly reduces the amount of times you draw them when you don't need them. While Karn has been a staple of the deck in the past, this is not the best Karn deck in the world. It mostly acts as an Ensnaring Bridge / Helm of Obedience split card, which is quite good, but not at its highest peak of power.
Overall, I like only playing a single Karn since it can certainly be clunky at times. Finally, Ill-Gotten Gains is an incredibly powerful card when combined with Leyline of the Void (since they don't get any cards). You couldn't reliably play this card in the deck in the past, since there are many situations where it isn't that good. However, as a tutor target it is the perfect inclusion for this deck and I love seeing it here.
4 Thoughtseize , 2 Hymn to Tourach
With black's rise in popularity, discard spells are in vogue again. Thoughtseize has become a dominant force in the meta game, and will always be one of the best cards to draw in your opening hand. There are a ton of powerful, consistent strategies in Legacy these days and having the ability to disrupt them for a single mana is incredibly important.
Hymn to Tourach is a lot slower than Thoughtseize , but the effect will always be a powerful one. This deck is perfectly set up to take advantage of Hymn to Tourach since it has the ability to follow it up with a haymaker, such as Sheoldred or Karn.
1 Pithing Needle , 1 Shadowspear
This is a very modest Saga package, but these are some of the better cards to have access to. Shadowspear makes your Saga tokens very threatening by themselves and enables you to win most race situations. Pithing Needle , on the other hand, is one of the most versatile spells in Legacy and the fact that you can have functionally 5 copies of it makes it the perfect inclusion.
2 Opposition Agent
Opposition Agent is an interesting card. The effect is not always the most powerful on turn 3, since there are a lot of decks that don't rely on tutoring. However, almost every deck utilizes fetchlands and being able to cast Opposition Agent on turn 1 with Dark Ritual can lock opponents out very easily. I think this makes having 2 copies very appealing, since it isn't the type of card you always want to draw, but it has its spots of being devastating.
4 Dark Ritual
There are so many powerful black cards in Legacy right now that Dark Ritual has significantly increased in stock. This card is at the core of the deck and certainly a major reason this deck is so powerful. While the stock has been steadily increasing over the past few years, Beseech the Mirror took the card over the edge. Being able to have access to just about every card in your deck following a Dark Ritual is extremely powerful and significantly increases this deck's consistency and versatility.
4 Chrome Mox
Chrome Mox can be a very costly card, but providing explosive ramp, as well as an artifact for Beseech the Mirror , is really important for this deck. Being able to cast a turn 1 Hymn to Tourach is very powerful and the fact that it enables turn 1 Beseech off a Dark Ritual is certainly nice. The cost of exiling a card from your hand is high, but this deck does have a few relatively dead draws, such as Leyline of the Void , which can be more freely pitched.
5 Swamp , 1 Snow-Covered Swamp , 2 Urborg, Tomb of Yawgmoth , 4 Vault of Whispers, 3 Agadeem's Awakening
This deck needs a lot of black sources in order to consistently cast its spells due to Beseech the Mirror . Being able to play 6 basic lands is really nice in Legacy. While Vault of Whispers is a worse Swamp in general, it significantly increases the consistency of Beseech the Mirror , so it is absolutely worth including. Urborg, Tomb of Yawgmoth makes Ancient Tomb /Urza's Saga tap for black, which is even better in this deck due to Beseech. Finally, Agadeem's Awakening is a fairly costly Swamp , but being able to work with Chrome Mox makes it an important inclusion.
3 Ancient Tomb
While Ancient Tomb is generally a staple in this type of deck, it does create a bit of tension with Beseech the Mirror . Still, it's among the most powerful lands in Legacy and it enables some of this deck's best starts, so it is absolutely worth including in large numbers here, but I understand the shift to 3 copies.
4 Urza's Saga is the glue that holds these decks together. It acts as a difficult-to-interact-with threat, which provides a ton of resilience in a deck like this. While this deck has a modest Saga package, turning Saga into a ramp spell for a black source is a big deal since this deck is leaning heavily into Beseech the Mirror . On top of all of that, Saga can be used to bargain Beseech, which is a small-but-meaningful upside. All of this makes Saga an easy include for this deck.
Sideboard Breakdown
1 Ensnaring Bridge , 1 Helm of Obedience
This is the Karn toolbox which, like the Saga targets, is very modest. Ensnaring Bridge has the ability to win the game straight up against certain archetypes and is a staple of these sideboards. Having access to a Helm is important for turning Karn into a real threat and increases the consistency of the deck even further.
4 Chalice of the Void
While Chalice is a part of the Karn toolbox, this is primarily here to sideboard as a haymaker against combo decks and decks relying on cheap spells. Chalice has been a key card in this type of deck in the past but I think it makes sense to move it into the sideboard for the time being. This deck is relying on Dark Ritual more than in the past and Chalice has fallen off in value in the metagame as a whole.
1 Damnation , 1 Tourach, Dread Cantor
These cards add to the Beseech toolbox. Damnation is a great card against creature decks that is generally too slow/clunky to play in larger quantities, so having it as a Beseech target is perfect. Tourach has been played in large numbers in the past but with Beseech in the mix it is not quite as necessary. You can still kick it after tutoring it, which is admittedly a bit expensive, but in the matchups where you're tutoring this that may be ok.
2 Plague Engineer
Plague Engineer sometimes feels a bit too slow in decks like Delver/Shadow, but seeing as this deck can power it out with Dark Ritual , it's the perfect inclusion here.
2 Opposition Agent
There are some decks that cannot beat an Opposition Agent , such as Doomsday, so siding up to 4 copies is very strong in certain matchups.
3 Sheoldred's Edict
Edict is a very versatile removal spell that answers a decent amount of problems, from card:Emrakul to Murktide Regent.
Helming Tips and Tricks
You can cast Chrome Mox without imprinting anything to get an artifact to bargain away.
In situations where you can't bargain Beseech, it still functions as a Diabolic Tutor, so keep those situations in mind.
Sideboard and Matchup Guide
Dimir Shadow
Out: 2 Opposition Agent , 1 Ill-Gotten Gains , 3 Chrome Mox : 3 Sheoldred's Edict , 2 Plague Engineer , 1 Damnation , 0-4 Chalice?
I could easily see a world where you want to bring in Chalice of the Void , since it can be very devastating against them. However, fair blue decks have more tools in general to allow them to play through that, such as Murktide Regent and Brazen Borrower.
That said, Murktide is significantly hampered by Leyline of the Void , so combining Leyline and Chalice could really put them in a bind. A decent amount of your cards are good in this matchup, so knowing what to cut is tricky. If Chalice is coming in, some number of Dark Ritual may be worth bringing out, and perhaps Chrome Mox increases in value.
For the most part, you have a lot of good pieces of interaction and a solid plan against them. I think this is a very reasonable matchup that is greatly benefitted from the inclusion of Beseech the Mirror .
4c Control
Out: 1 Shadowspear In: 1 Tourach, Dread Cantor
Most of your cards are good in the matchup to some extent, so I don't think you need to overdo it. Having a combo kill is great here since it can punish them for having too much removal. The fact that Beseech can get just the right card and provides you with access to your best cards more consistently is huge here and I think I'd be happy to be on the Mono Black side of the matchup.
WR Initiative
Out: 1 Ill-Gotten Gains , 1 Pithing Needle , 1 Hymn to Tourach In: 3 Sheoldred's Edict
There aren't that many cards to board in here, but having extra removal will be helpful. I could easily see it being correct to board in extra creatures so that you can steal the initiative back more often, but this deck doesn't have that much removal so I think relying on that is not going to be that effective.
While Leyline doesn't do much here, having a win condition in Leyline/Helm that can't be easily removed is excellent. In general, I think this may be a bit of a tougher matchup since they can apply a lot of pressure very quickly, but you certainly have the tools to overcome their strategy.
Doomsday
Out: 1 Shadowspear , 1 Pithing Needle , 1 Karn, the Great Creator, 1 Ill-Gotten Gains , 2 Leyline of the Void In: 2 Opposition Agent , 4 Chalice of the Void
While Opposition Agent is lights out against them, their strategy is designed to take advantage of decks like this. You definitely have the tools to play a competitive game, but if they have a fast hand there isn't much you can do. I like trimming on Leyline of the Void since it doesn't have any impact in the matchup outside of its combo potential, and starting down a card can be costly. In general, try to keep hands with disruption above all else, and try to apply some quick pressure, which is the combination you always need against this deck.
