Aha! Exploring Duplicate Mage in GvG

Mage has been in a very interesting spot since the release of GvG. There are so many viable decks and this is one of them!


Mage has been in a very interesting spot since the release of GvG. Whenever you queue into one on the ladder or see one in a tournament, you really can’t be sure what kind of deck the opponent is using. While Mech Mage has been the most common build on the ladder, we have also seen everything from Frescha’s Fatigue Mage to many different variants of Echo of Medivh Mage both on the ladder and in tournaments. Today I’m bringing to you yet another odd build of Mage, inspired by an early iteration of StrifeCro’s Mechplicate Mage, which utilized the strong early game of Mech Mage and developed into a strong late game with Archmage Antonidas and other high-cost legendary minions. This particular build, however, cuts most of the Mech synergy in favor of more consistent high value minions.


The premise of this deck is to utilize Duplicate in different ways to create favorable board positions against the opponent. Against aggro decks, we want to Duplicate our defensive cards, particularly Sludge Belcher and Antique Healbot. Against control, we have some more free rein, but our targets are typically our late game legendary minions, especially Archmage Antonidas and Sylvanas Windrunner. No matter what kind of deck our opponent is using, we almost always want to focus first on surviving. Given enough time, we have the firepower to take out any opponent with three or more copies of one of our legendary minions.

Card Choices

Zombie Chow

Every control deck needs some way to stave off early aggression. Unlike other classes, Mage has no weapons and limited early removal, making Zombie Chow a pretty obvious choice. For only one mana, we can usually trade for at least two early game minions from aggressive decks, and our Hero Power allows us to create favorable trades with Zombie Chow later on in the match. The life gain downside is irrelevant here. We aren’t looking to close out games early, but instead to delay the game until we can take out our opponent with an onslaught of high threat minions.

Annoy-o-Tron and Unstable Ghoul

I’ve included the two of these together because they serve a similar purpose: to handle swarms of minions and spread out damage among multiple targets. Annoy-o-Tron is also very strong against control classes when used properly, as its Divine Shield means your opponent will have to hit it twice before it is taken out. Against a turn four Mountain Giant from Handlock, for example, Annoy-o-Tron can soak up 16 damage that might otherwise go to your face. Unstable Ghoul isn’t quite as flexible, but it is incredibly strong against the common Haunted Creeper and can also bring higher health minions into a range where they can be picked off with our Hero Power.


This entire deck is built around utilizing Duplicate, and it is crucial when playing this deck to use it properly, especially when it is pulled early game with Mad Scientist‘s Deathrattle. Against control decks, you need to Duplicate something heavy, which can put you in a precarious position where you want to develop your board but simply cannot afford to do so. For this reason, it is important to consider your first few turns before you play them out. You might want to play a turn one Zombie Chow into a Mad Scientist, but if you Duplicate a Zombie Chow against Control Warrior, for example, you are probably going to lose because their threat density immediately becomes considerably higher than yours.

Mechanical Yeti

Mechanical Yeti is a very important card for the deck, but it isn’t an immediately obvious choice. Probably the most important reason to use it is because it offers a second midrange creature to fight for board control, but Mechanical Yeti is a great option over other four-mana minions because it provides us a Spare Part, which has incredible synergy with Archmage Antonidas. It is fairly safe to Duplicate Mechanical Yeti against aggro and midrange decks, where you won’t have enough time to play two or three copies of one of your legendary minions, but against control, it is better to save Duplicate for something more threatening.


Much like Mechanical Yeti, Toshley offers us two Spare Parts and a fantastic body for its cost. As a 5/7, Toshley trades well with Sludge Belcher, Loatheb, Shieldmaiden, and even the terrifying Savannah Highmane. It even has the potential to trade up with Dr. Boom and Ragnaros the Firelord in the event that it gives you a Reversing Switch. Something to note with Toshley is that you have to be very careful of your hand size when you play him. He immediately replaces himself in your hand with one Spare Part and gives you another after dying, and if you have up a Duplicate, two more cards will be added to your hand as well. It is very easy to overdraw when you play Toshley, especially because you typically want to save your Spare Parts until you can use them alongside Archmage Antonidas.

Archmage Antonidas

One of the strongest legendary minions in the game, Archmage Antonidas quickly found its way into the metagame as soon as Mage became a viable class. As I have mentioned many times already, Antonidas works so well in this deck alongside Spare Parts and Duplicate, and it will often win you entire games on its own. A very common play you’ll make is Archmage Antonidas + Duplicate on an empty board. Your opponent is forced to answer Antonidas or face the wrath of multiple Fireballs hitting their minions or their face, and when they do answer it, you will immediately gain two more copies. Even without Duplicating it, Antonidas can give you an insane amount of reach by giving you two or three Fireballs the turn you play him.


The mulligan strategy for this deck is pretty straightforward. Against Mage, Hunter, Paladin, and Warlock, you’ll want to mulligan aggressively for your early game cards. Search for Zombie Chow, Frostbolt, Annoy-o-Tron, and Unstable Ghoul. Keep Mad Scientist if the rest of your hand is good, and keep Explosive Sheep against Hunter, Paladin, and Warlock. Explosive Sheep is not as strong against Mage, as Mech Mage is filled with three Health minions, such as Snowchugger, Mechwarper, Harvest Golem, and the occasional Mana Wyrm.

Against control classes, you want Mad Scientist and Arcane Intellect to thin out your deck in the early game and assure you have the cards you need later on in the match. Against Warrior, Water Elemental is a good keep, as it can protect your minions from the opponent’s weapons by freezing him. Against Priest, Mechanical Yeti and Frostbolt are good choices to keep. Mechanical Yeti doesn’t fall to Shadow Word: Pain or Shadow Word: Death and trades well with Dark Cultist, while Frostbolt offers an immediate answer to Dark Cultist when used in conjunction with your Hero Power, as well as Northshire Cleric and an unhealed Injured Blademaster.

Never keep Secrets against any class. You always want to pull Ice Barrier from Mad Scientist, and you want to be able to manipulate your second Duplicate from your hand.


This is the only deck in Hearthstone I have ever played that has had a decent matchup against everything. The early game is strong enough to keep up against aggro decks, and the late game is strong enough to go toe-to-toe with control thanks to Duplicate. Midrange decks are the weakest matchups, but even they can still be easily defeated depending on your draw and theirs. Here are some tips for trickier matchups.


Never hit their face. No really, don’t. The easiest way to win this matchup is to deny the opponent the ability to play a Molten Giant for as long as possible. This becomes easier with the help of Zombie Chow, which you will often have in your opening hand because you should be using your mulligan to help you fight against Zoo. You want to use your early minions and Frostbolts to handle their early Mountain Giant or Twilight Drake and your Polymorphs to handle the others later on. You simply will not have the removal to handle Molten Giants on top of these, so the longer you can deny them, the better off you are. A wise Handlock player will use Lord Jaraxxus early on to pile on threats, but many of them will continue to Life Tap and eventually fatigue before they can kill you, which makes it easy for you to pick them off with Antonidas’s Fireballs.

Control Mage and Shaman

These are rare matchups at the moment. Most Mages will be running Mech Mage, and Shaman is uncommon in general. Still, they can be difficult if only for the reason that they can ruin your Duplicates with Hex and Polymorph. If they manage to use one of these cards on a threatening minion and then Duplicate it, you will be stuck with two Sheep or two Frogs. Thankfully, Shamans struggle with Sludge Belcher if you limit their board presence, so you can often lure a Hex with one of these early on in the match. Otherwise, Toshley is a good lure for Hex and Polymorph that can pave the way for you to Duplicate something else.


This deck is fairly refined, so running it as is will generally be your best bet. However, you might not have certain cards or the metagame might be in a place where you need to change some cards to have more favorable matchups. Here are some options if you find yourself needing to make card substitutions.

1x Polymorph > Big Game Hunter

This is the most immediate substitution that you might consider. With the ubiquity of Dr. Boom, Big Game Hunter is an obvious choice for most decks. The tempo swing you can gain from destroying a minion with Big Game Hunter is nearly incomparable, but the flexibility of Polymorph is generally preferred, as you will often gain board control with one big board sweep from Flamestrike or Explosive Sheep. Furthermore, Deathrattle minions such as Sylvanas Windrunner and Tirion Fordring are more threatening to this deck than most Big Game Hunter targets.


This is a card that many people simply don’t own. Toshley doesn’t find its way into many decks, so people often prefer to craft others instead. Still, as a legendary, Toshley’s ability is very unique, which makes him difficult to replace directly. Cairne Bloodhoof is the best option, as it can often trade with two or more minions or lure hard removal and this deck is slow enough that it isn’t difficult to use Cairne to his full value.

Ragnaros the Firelord

Ragnaros is an interesting card. He can single-handedly swing games in or against your favor, but when he works, he works incredibly well. He is also a fantastic Duplicate target, as he gives you immediate value upon coming into play. However, Ragnaros is the only Big Game Hunter target in the deck, which means he will almost always be destroyed by one. If you aren’t happy with how Ragnaros is working for you or you don’t own him, Kel’Thuzad is an interesting choice for a replacement. Although you will rarely have multiple minions on the board, Kel’Thuzad is not a target for Big Game Hunter, and he works extremely well with Duplicated minions, particularly Sylvanas, which will often stick after being played a second time. Sludge Belcher and Annoy-o-Tron also synergize especially well with Kel’Thuzad.

Dr. Boom

A lot of people are going to look at this decklist and wonder why there is no Dr. Boom. It is a valid concern; Dr. Boom is staple in almost every deck right now. However, Dr. Boom really isn’t ideal in this deck. While it is true that Dr. Boom applies an immense amount of immediate board pressure, it has terrible synergy with Duplicate. When your opponent sees an active Secret on your side of the field after you play Dr. Boom, they will be quick to take out a Boom Bot, triggering your Duplicate and losing you a lot of potential threat density.


I played this deck mostly throughout Season 9, from around rank 8 to rank 3. From there, I switched to faster decks, as this deck is fairly slow on the ladder. At that time, the metagame was less stable than it was now. People were still testing new decks, and even after that died down, there was still a pretty large variety of decks and classes. Now, we are beginning to see a lot of Druid and Paladin, which are two of the weaker matchups for the deck. However, I still maintained a positive win ratio against both classes last season, so the deck is still viable on the ladder right now. Thankfully, people are straying towards slower versions of both classes, which increases our win percentage against them. Still, the deck truly shines against aggro and control decks, so the deck gets better as the metagame speeds up or slows down.

I have been playing Hearthstone since just after the Open Beta release, and ever since, Mage has always been my favorite class. Unfortunately, aggressive Mages have almost always been favored over slower, control-oriented ones because of the reach their direct damage spells provide. This deck is a refreshing change for anyone looking to outwit their opponent and control the board with a final “Aha!” from Antonidas before you hear your opponent’s hero portrait crack.

If you have any questions, comments, or feedback, let me know in the comments below!