I played 100 games in diamond 5-1 mmr to test this deck, and it has a winrate of 76%.
Table of Contents
1. Win Conditions - General gameplan and win conditions against different deck types.
2. Matchups - Goes over the matchups you face for each class and provides some matchup specific tips.
3. Stats - Provides some stats for this deck's cards in terms of mulligan, drawn, and played winrate.
4. Mulligans - Some tips for the mulligan.
5. General Tips - General tips on playing this deck and card interactions to watch for.
6. Sample Games - At least one game vs each class to show the gameplay of this deck.
7. Conclusion - Some final thoughts on the deck.
1. Win Conditions
Against aggro: Use your removal cards to remove their boards and run them out of resources while using your healing to stay alive. Use deathrattle taunts to stall, and then lategame you can win by dropping N'Zoth, the Corruptor, Dragonqueen Alexstrasza, a Kazakus, Golem Shaper golem, or Shudderwock to take control of the board and easily push face.
Against combo: There are 2 ways this deck can beat combo. First is try to have a board presence, and use Loatheb, Shudderwock with a Loatheb effect, and Zephrys the Great and lethal them before they can combo. The other way is to use Dirty Rat, Mutanus the Devourer, and Shudderwock to repeat those effects to disrupt their combo. You can use Brann Bronzebeard to double up on these effects and Zola the Gorgon and Spirit Echo to get more copies of them.
Against control: You want to remove their boards and try to be greedy with your value. Use Diligent Notetaker and Spirit Echo as an infinite value combo, returning key minions to your hand indefinitely. Try to use Zola the Gorgon on Loatheb to play 2 of him, so that when you play Shudderwock your opponent won't be able to play spells on their turn. Feed Shudderwock further with Mutanus the Devourer and Dirty Rat to remove some of the value of the control deck, and play Dragonqueen Alexstrasza before as well to be able to have a large board protected by a double Loatheb effect as a finisher. You should also try to manipulate Zephrys the Great to give you Lord Jaraxxus, which can be done by playing him on turn 8 or later when you have 2 or less mana remaining. You can play Shudderwock just with multiple Mutanus the Devourer and Dirty Rat effects without Loatheb to get rid of opponent value and then try to win in fatigue or with Lord Jaraxxus if you didn't draw Loatheb and are near turn 10. Try to play N'Zoth, the Corruptor before Shudderwock to get an extra wave of deathrattles. Finally, you can sometimes use an infinite anti fatigue combo where you play White Eyes and Diligent Notetaker, then Spirit Echo. This will give a copy of the spell to your hand and both minions will go back to hand after they die, and then you can replay this combo again. White Eyes will keep shuffling The Storm Guardian into your deck and help prevent fatigue, potentially being key against control decks.
Aggro and combo matchups are a lot more straightforward than the control matchup, and you win against aggro and combo more often than you do against control. However, control matchups are very winnable if you maximize your value while using Dirty Rat and Mutanus the Devourer to minimize theirs, Loatheb to push for surprise lethals, big N'Zoth, the Corruptor boards, Shudderwock with different powerful effects, the infinite value and infinite anti fatigue combo especially if you can bait out their silence effects, and using Zephrys the Great to become Lord Jaraxxus.
Demon Hunter - Mostly odd demon hunters, you have a lot of removal and healing as well as taunts so should be very favored.
Druid - A lot of slow combo druids that you can destroy with Mutanus the Devourer and Dirty Rat and using Shudderwock to repeat those battlecries. Sometimes you can even use Loatheb to win by board pressure. Very favored. Also a lot of aggro druid which you should destroy with all your removals and heals, so also very favored.
Hunter - Mostly even hunters, you are again very favored due to all your heals and removals.
Mage - Some combo mages, feels slightly favored because of all your combo disruption. Reno mage was rare but very favored, they just can't deal with your Shudderwock and Loatheb effect most of the time. Secret mage was very common and even, really depends on Zephrys the Great and Reno Jackson. A tip is before playing the Firemancer Flurgl and Toxfin combo to wipe their board test for Explosive Runes.
Paladin - Very favored against odd paladins, you have too much removals for them to handle and after you drop a N'Zoth, the Corruptor you will just take over the board.
Priest - Very favored vs reno priests, you have a lot of disruption to ruin their combo and Bad Luck Albatross to shut down their strongest cards. Favored vs big priests, you need to use your removals well and bait them to maximize value and use Devolve and Zephrys the Great to ruin their ress pool as well as use Bad Luck Albatross to try and get birds into it. You can sometimes win with Shudderwock or Loatheb but running them out of resources and winning in fatigue is very doable.
Rogue - Mostly kingsbane rogues, it's favored because you can keep their board clear and play taunts to stop face damage from their weapon and then win in the lategame after you establish a board.
Shaman - Reno Shaman is very favored, most Reno Shamans are a pure combo version right now so you can disrupt them better than they can disrupt you, while having Bad Luck Albatross as an additional tool to shut them down in both their powerful cards and delaying their draws to get to their combo. You have a lot of value and don't care even if your Shudderwock is destroyed in this matchup while they just lose if you can hit a key combo piece like Shudderwock or Grumble, Worldshaker. Murloc shaman is also very favored, if you remove their early waves then they run out of value and Zephrys the Great into Hungry Crab early can win you board control.
Warlock - Reno warlock was favored, they sometimes have Tickatus but you have a lot of removals and Devolve for their boards and Shudderwock with a Loatheb effect is a good finisher. You also have Mutanus the Devourer and Dirty Rat effects which sometimes win you the game. Finally, White Eyes helps you avoid fatigue even after Tickatus while Bad Luck Albatross shuts down a lot of their key cards. Discard warlock was favored, you have to just keep the board clear and eventually they run out of value and fatigue. Darkglare warlock was even, you have Toxfin and Firemancer Flurgl to deal with their Loatheb turn.
Warrior - Odd warrior is favored as you should have too much value for them to handle, pirate warrior is also favored as you can shut down their board with removals and then prevent their weapons from doing any face damage with taunts.
Here are some stats regarding mulligan winrate, drawn winrate, and played winrate for the cards in this deck.
These cards are joint MVP, as you use them together and they top this list. The Firemancer Flurgl into Toxfin combo is incredibly powerful, it's a 3 mana one sided board clear that can even be played after Loatheb shuts down spell based clears. Ice Fishing, which often gets you this combo in hand, is the 3rd best card by played winrate which further shows just how powerful this combo is.
Keep Zephrys the Great.
Keep Maelstrom Portal if against paladin, druid or rogue.
Keep Reno Jackson unless against priest.
Keep Dirty Rat against druid, it's good against both combo druid and aggro druid.
Keep Hagatha's Scheme but only if you have some lower cost cards to play.
Keep Doomsayer against all classes other than priest and warlock.
5. General Tips
Diligent Notetaker + Spirit Echo = Infinite value. Diligent Notetaker will give you another copy of Spirit Echo and will itself go back to your hand when it dies. In most cases you should use these cards individually, but it's something to look for in matchups where you need value. You can keep using this to copy any other minions including the Firemancer Flurgl and Toxfin combo. It's vulnerable to silence but many decks don't run silence now. Another useful minion to keep copying in certain matchups is White Eyes to prevent fatigue.
Be aware that multiple copies of The Storm Guardian in your deck from White Eyes can shut off your no duplicate cards, so play your no duplicate cards first before playing N'Zoth, the Corruptor or doing the infinite anti fatigue endgame.
For Kazakus, Golem Shaper a great golem to look for against big priest is the 10 mana poisonous one with battlecry deal 3 damage to all minions. It's a big body and one sided board clear.
You can use Doomsayer after a board clear in the midgame on an empty board to make your aggro opponent skip their next turn, and not play any minions. Then next turn you will have the initiative.
Unless you are desperate, you should wait to draw one murloc before playing Ice Fishing. This increases the probability to have all 3 murlocs in hand earlier in the game.
Try to keep track of what battlecries you have played to plan your Shudderwock turn. Mutanus the Devourer and Dirty Rat are great vs combo decks, Loatheb and especially Loatheb into Zola the Gorgon into another Loatheb or a N'Zoth, the Corruptor board can be great for a finisher versus control decks. Reno Jackson will make Shudderwock an extra heal and is great vs aggro. Also do not wait for full value for Shudderwock before playing it, in most cases it's better to play it early as a power turn especially against aggro.
6. Sample Games
Odd Demon Hunter: https://hsreplay.net/replay/oFrrmgQ5tfPxKQVihyxRUn
Aggro Druid: https://hsreplay.net/replay/txPrGAhHHZGyVxaVMQhLCE
Combo Druid: https://hsreplay.net/replay/pznVA9uVZfXTkWjopGSABD
Even Hunter: https://hsreplay.net/replay/c3gAfQ2GgR6PFoXsGruXQM
Secret Mage: https://hsreplay.net/replay/3mwUK9hBn3oG9TDVFzYLGA
Odd Paladin: https://hsreplay.net/replay/RJZWJDexxyYhET4P6ByAmj
Reno Priest: https://hsreplay.net/replay/DMBHHQ83gyENmhQRFgHhy2
Kingsbane Rogue: https://hsreplay.net/replay/5mJnfU9D3wTmYgMViM6avY
Murloc Shaman: https://hsreplay.net/replay/4Gh8RVh5TwenVwNyGtrKHc
Reno Combo Shaman: https://hsreplay.net/replay/L5Z4XHB28nZfS7KpcvcB9Q
Darkglare Warlock: https://hsreplay.net/replay/gM4vCE4tMWKX7PJsGhNSuA
Reno Warlock: https://hsreplay.net/replay/FA8LWDSNZcBgEBxDtjQ6b4
Reno Warrior: https://hsreplay.net/replay/vApJjN6REDk4UYWh5rpBy7
This is actually my single favorite deck in Hearthstone. It's both very fun with tons of value and interesting card interactions and has a high winrate against a wide variety of deck archetypes. Compared to the Reno Galakrond Shaman I posted a week ago (https://www.hearthpwn.com/decks/1390355-legend-68-winrate-reno-galakrond-shaman) which was legend viable, this deck does slightly worse against mages but is generally better against everything else and so has an 8% higher overall winrate, so getting legend with this one should be even easier. If you have any questions, comments, or suggestions please write them below.