Caster Cup Top 8 Gaasyendietha OTK Combo Deck Profile + Strategy Guide

Greetings casters! With the $250,000 Caster’s Cup coming to an end, I’m sure everyone out there is eager to see all the great new decks and strategies from the best of the best! Today I have a unique Torrential River / Gaasyendietha combo deck list + strategy guide for you. Before I get into the deck list, I would like to introduce myself and my teammates as we are newer to the Metazoo community.

My name is Nick Blandin, and my teammates Steve Silverman and Fred Chang all played this deck with a top 16 and top 8 finish respectively between the three of us. We all have extensive histories in competitive TCGS at the highest level across a multitude of card games. Steve Silverman is one of the most well-known Yugioh and VS System competitors there is, with a plethora of premier event tops, multiple time YCS champion, and world championship competitor. Fred Chang was a competitive Flesh and Blood player making semi-finals at his first calling event before deciding to switch over to Metazoo. I’ve been competing at the highest level in a variety of TCGs since I was about 15 years old including Yugioh, Hearthstone, Force of Will (FOW), Legends of Runeterra, and many more. Over the years I have accomplished a lot in these TCGs including being a YCS finalist, multiple premier event tops in Yugioh, 3x FOW championship winner, FOW National and World Champion, and a top ranked ladder player in Runeterra/Hearthstone.

We recently decided to take our TCG expertise to Metazoo and without further ado, the deck we came up with for the Caster’s Cup!

Beasties (2)

2 Gaasyendietha

Auras (10)

6 Water Aura
2 Flame Aura
2 Prism Aura

Artifacts (6)

2 Megalodon Tooth
2 Mermaid Scales
1 Chaos Crystal
1 Forest Gods Amber

Spells (20)

3 Torrential River
3 Tidal Pull
2 Flood the Earth
1 River.of Time
1 Dampen
1 New Years New Beginnings
1 Crossroads
2 Absorb aura
3 Boil over
2 Bookmark
1 Growth

Terra (2)

1 Overgrown City
1 River.

Side deck (15)

2 Dampen
2 First Anniversary Celebration
1 Absorb Aura
1 Overgrown City
2 Wallowa Lake Crustacean
3 Loveland Mailman
4 Smokey Spirits

We believe this to be the best deck and we decided to play it as it doesn’t have any bad matchups and most decks can’t interact with/stop the deck. There are a lot of nuances to playing this deck that make it without a doubt the hardest deck to play in the game currently (10/10 difficulty level). I will try to build a foundation for you to learn the deck and improve from the ground up.

To start off, I think it’s important to understand what the win condition of the deck is and how the combo works before diving into advanced strategy. Gaasyendietha allows you to contract each spell from your cemetery one time (per copy) which combines with Boil Over and Torrential River to kill your opponent in one turn. Note, you must control an aura with a matching type to contract a spell with this effect so you will need one Flame Aura in play. Boil Over will be contracted three times from your hand, and then an additional three times from the cemetery (only costing three total aura, due to Boil Over’s effect that makes it cost zero aura after the first one). Then, you will contract Torrential River once to activate its lingering effect for the turn “each time you Contract a Water Page this turn Bookmark one and deal 30 Damage to target Page or Caster”. After the first Torrential River it’s time to unleash the damage, but instead of our opponent we will be targeting ourselves! Each time you contract a water page you will take 30 damage, which will deal 180 damage back to your opponent from the 6x Boil Over stacks. You will then contract all your remaining copies of Torrential River for ZERO AURA due to its first effect. After contracting all the copies in your hand, you can contract them each 1 additional time from your cemetery with Gaasyendietha as well as any other water pages. You will continue to utilize this effect to contract as many water pages as you can until your opponent has no LP left! Sometimes you may need to attack with Gaasyendietha as the final piece of damage to win (be sure to keep track of his passive attack buff).

Now that we understand how our combo works let’s jump into how we set up the combo and general strategies of how to accomplish this.  Typically the set up for this will be playing Gaasyendietha, as many aura generating artifacts as you can, and a River.of Time generally on your turn 5-7 (in some cases even sooner!). This allows you to go into 1 additional turn with all your current and additional aura (from artifacts) awakened. Assuming you were on your turn 6 for example, you will have 6 aura in play, and another 6-7 aura from your artifacts, for a total of 12-13 aura on your following turn + 1 aura played on this turn (this is an average scenario, sometimes you will have slightly more or less). For this setup you will need to have a River. and a Flame Aura in play. This is to make sure you can contract River.of Time for 1 aura and use all your Boil Overs to ensure a win on your extra turn. The gameplan leading up to this turn has 2 primary objectives, draw AS MANY cards as possible (ideally have under 5 cards in deck on your combo turn) and make sure you don’t lose too much life/die (the combo usually requires you to have more than 180LP). It is VERY important to mulligan with this in mind, as the best opening hands are usually based on how many cards they can draw. Tidal pull, bookmark, and new year’s new beginnings are the best cards for you to see in your opening hand accompanied by 1-2 aura. You often do not need to worry about cards beyond these in your opening hand, as drawing more cards will find you what you need as the game progresses. Most decks will not be able to attack you fast enough to put your life total low enough before your combo. However, a good Torrential River turn, or Flood the Earth, will generally be enough to keep you alive against even the most aggressive decks. Now that we’ve covered the combo and basic strategy, I think it’s time to dive into the intricacies of the deck that will be the deciding factors in winning or losing games.


Always be aware of what your maximum damage threshold is, there is a lot of variables that will adjust your total damage output. If you go all in targeting your opponent’s LP without winning the game you’ll almost always lose.

Example: If you have 1 boil over in the cemetery already, your combo turn will now only include 5 stacks instead of 6. This will now require you to trigger torrential river 7 times, which costs more aura and LP. For each Torrential River in your cemetery, that’s 1 less 0 aura trigger to deal 30 more damage. Be sure to consider all the variables ahead of time including total aura, number of playable water pages and aura required, total LP remaining for both players, total boil overs, total 0 cost triggers for torrential river, cards in deck that can be drawn on combo turn for extra damage (ex: Megalodon Tooth or more Torrential Rivers), potential aura needed for Dampen or Crossroads, etc.


You will often find yourself holding a Torrential River ready to go at various points in the game. It’s important to note that you will often only be spending 1-2 turns in the game destroying your opponent’s beasties. If you’re playing against a more aggressive deck, you’ll need to utilize it to destroy as many beasties as you can, while against slower decks it’s okay to use it to draw cards faster. With multiple copies of Torrential River in hand, it’s often better to use them on separate turns to solidify your victory after they rebuild their board from the first one (against aggro) or draw more cards through the game (against slower decks). Be sure to evaluate the situation to consider how many turns it will take for you opponent to kill you with their current board + 1-2 additional beasties/Lightning in a Bottles. You don’t need that much LP to beat your opponent so going down to about 210-240LP is fine. When you foresee your life going below this point before you can combo this is where you’ll be forced to torrential river sooner rather than later. Be sure to maximize your Torrential Rivers triggers by holding water artifacts and a Water Aura for the turn you use it when possible.


In dire situations you may not be able to win the game on your combo turn and waiting any longer would result in losing. Instead of just accepting defeat in these situations, you use your combo turn to kill everything they have with Gaasyendietha + Torrential River. If this was your first copy of Gaasyendietha, then you can still win the game at a later point with your 2nd copy without River.of Time. If it’s your 2nd copy and they can’t draw an answer to the Gaasyendietha, you still have a chance to win in the next turn or 2 and you will have regained a win from a “lost” game!


You will need to make sure you don’t lose your 2nd copy of both Gaasyendietha and Flame Aura (you likely auto lose the game if this happens), and you will want to make sure you don’t lose your River. or any Boil Overs. The primary way these cards are at risk of going away is New Year’s New Beginnings. Tidal Pull and Crossroads will be the main ways you protect your cards in this deck (and you can just play the River. most of the time). Tidal Pull should often be placing these cards at the bottom of your deck as they’re not needed until your combo turn (where you will have drawn through your whole deck). Crossroads is the sleeper MVP of the deck and will allow you to pick up one of your essential combo pieces in the event you discard your last copy of one of them. Sometimes you will have to run out your first copy of Gaasyendietha to draw through your deck or make a big torrential river turn to stay alive and this is completely fine, just make sure you don’t lose the 2nd copy.



Deck is generally too slow to kill you, but you need to watch out for a big Chessie + Lightning in a Bottle turn/Dampen. Torrential River effectively deals with their beasties to keep you alive and then try to make sure you have a Dampen of your own to counter their copy if they have the aura available.
Sideboard: Put in extra copy of Dampen for an Absorb Aura

Fearsome Critters/Cosmic/Lightning:

These are very beastie focused decks that will try to play aggressively. Overgrown City is important to help you get to Flood the Earth faster. After playing a Flood the Earth or having a big Torrential River turn, they generally can’t rebuild their board fast enough and the game is secured.

Sideboard: Put in additional Overgrown City and First Anniversary Celebration (for Lightning). This gets you to Flood the Earth faster and make sure it destroys every beastie against Lightning (First Anniversary Celebration will make it so flying beasties get destroyed). You can take out Forest Gods Amber, Growth, and Absorb aura.

If you’ve made it this far, I’d like to thank you for reading my first competitive Metazoo article! That concludes the deck guide and I hope you have as much success with this deck as we did!

6 replies on “Caster Cup Top 8 Gaasyendietha OTK Combo Deck Profile + Strategy Guide”

I could be wrong but from how I understand it, First Anniversary Celebration nullifies traits rather than removes them meaning that they still have the traits but they are not active. From that understanding, I don’t believe flood the earth would destroy flying beasties. Please let me know if I am wrong or if there is some ruling I’m not aware of.

Should metazoo do an Errata to the text of one or both of the two cards then? Toxic water says remove but First Anniversary does not. Flood the earth does not say that the trait needs to be active.

Metazoo has now changed the ruling to my interpretation of how the cards work. Flood the earth DOES NOT kill flying beasties which have had their flying nullified

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