Mermail Atlanteans were a previously hyped archetype in Gaia Genesis that saw no competitive play due to severe inconsistencies. Since the release of Cybernetic Rebellion, however, the deck went from competitively unplayable to a potential future contender for the Tier List. The box includes a searcher in Mermail Abyssteus, and special summoning capability in Deep Sea Diva, Mermail Abysslinde, and Abyss-sphere. It is important, however, to realize that even though more special summoning has been included, this deck is still considered glass cannon; therefore, playing over-aggressively is not advised. Despite having the potential to be glass cannon, Mermail Atlantean no longer suffering an inevitable lacklustre turn 1 makes the archetype more reliable in competitive play.
Much like the Vampire archetype, Mermail Atlanteans are considered a “toolbox” archetype. Most Mermail monsters have the ability to discard a water monster to activate an effect. Atlanteans compliment these discards because each Atlantean gets an effect themselves when sent to the Graveyard to activate a water monster’s effect. As it turns out, Mermail monsters are the ones adding as well as special summoning other monsters, while Atlantean monsters are the ones destroying cards on the field. Moreover, Mermail monsters can only use their effects once per turn, while Atlantean monsters can use their effect more than once in a turn. The main strategy of the deck is to out problematic cards with Atlantean effects so that boss monsters can be summoned without issue.
To get the maximum amount of utility from this guide, it is integral among knowing basic Yu-Gi-Oh mechanics that you also know how to use the toggle button, how to read delays, as well as how chain links work. All of these concepts will be mentioned in the guide.
Since Mermails are complimented well with Atlanteans, the deck does not have a ton of room for tech options. Core cards will be split into Mermails, Atlanteans, Abyss spells and traps, and other useful cards that can help this deck, but are not necessarily integral to the main strategy.
Mermail Abyssteus (2-3x):
Being the main searcher of the deck, it is important to have at least 2 of this card, but 3 is ideal. Having both a discard outlet to special summon and a search effect for a level 4 or lower Mermail helps with tutoring Atlantean destructions and consistency respectively.
Mermail Abyssmegalo (1-2x):
Abyssmegalo is the boss monster of the deck. Being able to search an Abyss spell/trap, as well as having the potential to attack twice in a turn, makes Abyssmegalo scary to deal with. It is more likely that you will summon him off of Mermail Abysslinde or Abyss-sphere since 2 water discards leaves you susceptible to a Treacherous Trap Hole.
Mermail Abysslinde (2-3x):
Abysslinde is extremely strong, especially in conjunction with Abyss-sphere. Having access to any Mermail in the deck when it is destroyed by battle or card effect is extremely relevant.
Atlantean Heavy Infantry (2-3x):
Arguably the best Atlantean, but it is dependent on the format. Being able to out face-up monsters gives the deck notable strength over decks that like to “protect the castle”.
Atlantean Marksman (2-3x):
Marksman is your best Deep Sea Diva target, while also being a way of destroying set cards. Being able to destroy sets is useful in terms of making pushes for lethal.
Deep Sea Diva (2-3x):
Diva is the second strongest Tuner in the game, second to The White Stone of Ancients. On top of being able to summon Synchros, it enables other combos, which will be mentioned below.
Easily the strongest of the Abyss spell and traps. Being able to summon any Mermail from the deck (usually Abysslinde) opens up lots of potential for the deck. Be careful with your use of Sphere if you are running spells since it will not allow you to use them while face-up. Moreover, if you are using this trap during your opponent’s turn, make sure to use it BEFORE their End Phase because if you use it then, you will have to wait until your opponent’s next End Phase. Activate Sphere when it says your opponent is about to end their Main Phase.
Mermail Abyssleed (0-1x):
Abysslead is the main monster you are summoning off of Abysslinde. With its 2700 attack, it can attack over Elemental HERO Brave Neos with 1 Neos in Grave (likely from Neos Fusion), as well as Legendary Six Samurai - Shi En. You will never use his discard effect since you have to send 3, but it is possible to use the other effect to discard a random card from the opponent’s hand; unfortunately, since the effect is limited to tributing Mermails, this effect is also less useful.
Mermail Abyssocea (0-1x):
Mermail Abyssocea did not make the list for mandatory cards because it has too many restrictions. With 3 monster card zones, you will never be able to summon 2 Mermails off of Mermail Abyssteus since it stays on the field until both monsters are summoned. Moreover, sending after causes Mermail Abysspike and Mermail Abyssturge to miss timing. Despite its limitations, it can tribute itself for a copy of Mermail Abysslinde, so it is not a terrible option if you are wanting to see her faster.
Abyss Soldier (0-2x):
While a non-searchable water monster, it has one of the strongest effects to offer. Being able to provide a discard outlet to return a card not only helps with removing problematic cards, but also to clear the way for bigger investments like Mermail Abyssmegalo.
Dragon Ice (0-1x):
Dragon Ice is a powerful card that disrupts special summons, especially if you are holding an Atlantean Heavy Infantry in your hand. Moreover, it’s a card that easily helps Deep Sea Diva make level 7 and level 9 Synchros.
While unsearchable, Salvage is an amazing card to topdeck. With Deep Sea Diva and Mermail Abysslinde, it is fairly easy to meet the requirements of Salvage. This card can easily be used alongside or replaced by Mermail Abyssturge, but the downside to not running Abyssturge is that you will be able to recycle from the graveyard less often.
Geomancer of the Ice Barrier (0-1x):
While a little odd to include a random Ice Barrier card, this is a level 3 Tuner that you can search with Mermail Abysspike. Searching this at the end phase with Abyss-sphere destroying Abysslinde will allow you to potentially make Gungnir, Dragon of the Ice Barrier or Black Rose Dragon easier. Moreover, it does have a discard effect to use if need be.
Genex Undine (1-3x) and Genex Controller (1-2):
Undine is notable since it allows you to send key cards like Dragon Ice, as well as Atlanteans to the graveyard. Moreover, Controller can possibly be used later for a level 5-7 synchro. Undine can be searched out via Mermail Abysspike, so 1 Undine 1 Controller is sufficient if you want it as an option; however, if you play higher ratios, you will likely be using closer to 30 cards.
Legendary Atlantean Tridon (0-1x) and Poseidra, the Atlantean Dragon (0-1):
This 2 card package can be used as another option for Deep Sea Diva. Tridon can tribute itself off and Diva to summon Poseidra. The relevance with this is your opponent’s monsters also lose 300 attack in the process, so this would allow Poseidra to attack over threats like Ancient Gear Reactor Dragon, Blue-Eyes White Dragon, and even go point to point with Cosmo Brain if necessary.
Citadel Whale (0-1x) and Sea Stealth Attack (0-1):
While not an advised package in a meta with Cosmic Cyclone, Citadel Whale is easier to make now with Deep Sea Diva. Moreover, tributing an Atlantean monster to summon Whale will allow its effect to activate alongside Whale.
Abyss-Scale of Cetus (0-1x), Abyss-Scale of the Kraken (0-1) and Abyss-Scale of the Mizuchi (0-1x)
While not advised cards to run since they are Equip spells, they can be searched out via Megalo to make it more of a threat. Moreover, each equip has a built in negation of trap, monster effect, and spell respectively, so it can be strong if you are ahead in advantage; however, the downside of the equips is it will negate the first trap, monster effect, or spell used by the opponent, so you are unable to be selective with your negate.
Main Deck Techs and Side Deck Cards
Relevant Extra Deck Cards
Sealed Tombs is the best ability to run with Mermail Atlanteans in general. Tombs allows Atlantean Heavy Infantry to kill problematic cards like Elemental HERO Brave Neos with ease, and it has multiple intrinsic uses outside of that, which will be mentioned in the matchups. Overall the best all-around ability you could play, so it is definitely worth at least siding should tournaments allow you to side deck an ability.
Beatdown is arguably just as good as Sealed Tombs, but only on ladder. Since Mermails are able to summon multiple high level Mermails easily, Beatdown is a relevant option to help in the mirror matchup, as well as other matchups that have high attack monsters. Beatdown is shadowed by Sealed Tombs for the sole purpose that certain matchups like Spellbooks and Six Samurai become more annoying to deal with if you are not running Sealed Tombs.
Mythic Depths is another possibility if Citadel Whale and Sea Stealth Attack are being included in the deck. Unfortunately, Cosmic Cyclone is common to see in competitive play, especially in side-deck format; however, Mythic Depths is another solid consideration on ladder or in tournaments that allow you to side deck an ability (play Mythic Depths game 1 and switch to Sealed Tombs for Game 2 and/or 3).
Easily the least relevant of the relevant abilities, but with the release of Deep Sea Diva, it is easier to toolbox your Extra Deck. Moreover, Level Duplication will become even more relevant when XYZs are released in the future.
Since Mermails and Atlanteans need to work together to be effective, most of these combos will involve 2-3 cards.
- Combo #1
After setting Mermail Abysslinde/Abyss-sphere, when your Mermail Abysslinde goes to the graveyard, you can summon Mermail Abysspike, who will discard Mermail Abyssgunde to add any level 3 Water monster. Mermail Abyssgunde’s effect will then activate to revive your Mermail Abysslinde.
- Combo #2
Similar to the last combo, you will be relying on the destruction of Mermail Abysslinde to summon Mermail Abysspike. The difference with this combo is that you will preemptively use Sealed Tombs. This combo is reliant on Abyss-sphere to get Abysslinde out because Abyss-Sphere guarantees that Mermail Abysslinde will get destroyed when Sealed Tombs is live; therefore, when you summon Mermail Abysspike and discard Heavy Infantry for a level 3 Water monster, Heavy Infantry will kill threats like Elemental HERO Brave Neos easier.
- Combo #3
One of the most important chain blocks this deck has. Since Atlantean effects are mandatory and Mermail effects are optional, Atlantean Heavy Infantry will activate as Chain Link 1, and Mermail Abyssteus will activate as Chain Link 2. This is critical against cards like Red-Eyes Slash Dragon because it will be unable to negate Atlantean Heavy Infantry’s effect, resulting in its destruction except if it has an equipped Power of the Guardians with 1 counter. Combined with Sealed Tombs, Mermail Abyssteus and Atleantean Heavy Infantry is one of your deadliest 2 card combos in the deck.
- Combo #4
With a Mermail Card.
Having access to Level Duplication, this is the most versatile ways to access the extra deck. You summon Deep Sea Diva and summon either Atlantean Heavy Infantry or Atlantean Marksman. Next, use Level Duplication to change the level of one of your monsters. If you reveal a level 7 Mermail, you can make a level 9 Synchro. Moreover, if you decide to summon Atlantean Marksman and reveal a level 4 Mermail, you have the option of either making a level 6 or level 7 Synchro.
- Combo #5
White Aura Dolphin is hands down the most broken Level 6 Synchro in Mermail Atlanteans; unfortunately, there are not a lot of ways to summon this card. Fortunately, with the ability Level Duplication, it is a lot easier. Like the first two combos, you will use Sphere just before the End Phase to summon Mermail Abysslinde, and then Abysslinde will summon Mermail Abysspike when destroyed. Discard your Water monster to add Geomancer of the Ice Barrier. On your turn, use Level Duplication to make your Mermail Abysspike level 3 by revealing the Geomancer of the Ice Barrier, and then summon it so you can Synchro summon into White Aura Dolphin.
- Combo #6
With a Water Monster.
Easily my favourite 3 card combo. If your Water monster in hand is an Atlantean Marksman, you will want to special summon Mermail Abyssteus first to clear a potential backrow. Otherwise, normal summon Deep Sea Diva first and special summon Atlantean Marksman with her effect. Next, discard your water monster to special summon Mermail Abyssturge and add any level 4 or lower Mermail. Next, Synchro summon into Vermillion Dragon Mech. Vermillion Dragon Mech will allow you to pop a card by banishing Diva. Moreover, with Vermillion Mech Dragon and Atlantean Marksman on board while your opponent has no monsters, you can potentially attack for lethal (4100 damage).
- Combo #7
With a Mermail Card.
Having these 3 cards can generate an OTK. Activate Mermail Abyssmegalo to send Mermail Abyssgunde and the other Mermail monster to summon it. Generally, you want to add an Abyss-Sphere if you do not have game; however, if you can go for game, you will want to search an Abyss Equip Spell card, preferably Abyss-Scale of Cetus. Abyssgunde will summon the other discarded Mermail, and then you can use Megalo’s effect to send that Mermail so it can attack twice for 3200 and be protected from a Trap Card.
- Combo #8
With a another Mermail Card.
This combo will allow you to maximize your resources. Activate Mermail Abyssteus to send the other Mermail monster to special summon it. Then, add either Mermail Abysspike or Mermail Abyssgunde (whichever you do not have) with Mermail Abyssteus’ effect. Next, normal summon Mermail Abysspike and discard Mermail Abyssgunde to add any level 3 Water monster. Finally, Mermail Abyssgunde will summon the Mermail you discarded previously with Mermail Abyssteus.
- Combo #9
This Combo is exactly the same as the one above, except with the Quick-play Spell Concentrating Current. After popping a monster, attempt to attack directly with Mermail Abyssteus. Most players will allow the attack to go through if they are at 4000 LP, so in the Damage Step, you will use Concentrating Current, which will boost Mermail Abyssteus to 4100, thus generating lethal off of a seemingly innocent direct attack.
Keep in mind that I have excluded 4+ card combos because they are highly situational; however, most 4 card combos involve any of the combos above with an extender. The extender allows for either more OTKs or card advantage, so keep that in the back of your head while considering the combos you can make.
We have now gotten to the most important part of the guide: The matchups. Each matchup will involve opinions on how Mermails fare against the other deck, as well as possible side deck/tech options for the matchup specifically.
Six Samurai can be a real tough matchup if Sealed Tombs is not being played. One of the main issues of not running Tombs is that Atlantean Heavy Infantry becomes a less reliable factor in destroying their monsters due to Secret Six Samurai monsters protecting against solo destruction. Moreover, World Legacy Clash can outright win some games by protecting Legendary Six Samurai - Shi En, and Legendary Six Samurai - Enishi can bounce a bigger card. With Sealed Tombs, however, the matchup is closer to even, with Six Samurai still having a slightly better win rate. Being able to out a solo Legendary Six Samurai - Shi En, as well as shutting down Legendary Six Samurai Enishi, are both critical factors that Mermail Atlantean players need to exploit in that turn of Sealed Tombs; therefore, when you use Sealed Tombs, make sure you can make a strong play. Abyss Soldier is one of the strongest techs/side cards you can play because with Sealed Tombs, it can out boards like Legendary Six Samurai - Shi En and Legendary Six Samurai Enishi by himself. If Mermail Atlanteans are able to successfully exploit Six Samurai in the turn of Sealed Tombs, they will likely win the game; however, if Six Samurai has World Legacy Clash or a well-timed Six Style - Dual Wield, it is likely that Mermail Atlanteans will lose.
Ancient Gears are about an even matchup for Mermail Atlanteans. Having access to destruction in Atlantean Heavy Infantry is critical in the matchup. When they summon Ancient Gear Reactor Dragon, it is important to have Abyss-sphere ready as a method to discard a potential Infantry in hand. You can do this by summoning Mermail Abysspike directly. While Mermail Abysspike will not be able to use its search effect due to being negated by Abyss-sphere, Mermail Abysspike will still discard as a cost, allowing Atlantean Heavy Infantry to destroy Ancient Gear Reactor Dragon. This is critical to do right away because a well-timed Ancient Gear Fortress will win Ancient Gears the game.
Sealed Tombs is still relevant since it can stop Galaxy Cyclone from banishing, in addition to preventing the special summon of an Ancient Gear from the Graveyard. Cosmic Cyclone is huge in this matchup since it can remove potential threats like Geartown and Fortress if they are being targeted for destruction, as well as Castle to prevent a tribute summon of Reactor from the hand. Moreover, the overall versatility of Cosmic Cyclone makes it a must in the side deck.
Red-Eyes is about an even matchup, but Power of the Guardians tips the matchup in Red-Eyes’ favour. It is critical to run Triple Atlantean Heavy Infantry in order to maximize your chances of succeeding with a chain block. You will get a chain block either with Mermail Abyssteus and Atlantean Heavy Infantry or Mermail Abyssmegalo, Atlantean Heavy Infantry, and another Water monster. When you summon either Mermail Abyssteus or Mermail Abyssmegalo, Atlantean Heavy Infantry will activate before the special summoned Mermail since it is a mandatory effect. Next, your special summoned Mermail will activate their effect. Using the effect to search will eliminate the window of opportunity for Red-Eyes Slash Dragon to negate the destruction. Combine this with Sealed Tombs, and the Red-Eyes player gets nothing from the destruction. Power of the Guardians, however, will make this chain block difficult or impossible, depending on the number of counters on it. If the Red-Eyes player has a Red-Eyes Slash Dragon with an equipped Power of the Guardians with one counter, your only hope of breaking the board is having Mermail Abyssmegalo and 2 Atlantean Heavy Infantry. Using a copy of Salvage in your main deck can be beneficial in order to acquire this hand. In this case, you will want to target Red-Eyes Slash Dragon with the first Atlantean Heavy Infantry and Power of the Guardians with the second copy since the chain resolves backwards and will pop the Equip Spell first. Drowning Mirror Force is a solid option to consider in the side deck when facing Red-Eyes. Additionally, thanks to Deep Sea Diva, it is somewhat easy to resolve A Major Upset and Share the Pain without losing too much card advantage, so those cards can also work in the side deck.
Blue-Eyes is arguably the hardest matchup Mermails can face. The only thing that Mermail has going against Blue-Eyes is the fact that Sealed Tombs is more or less useless against Mermail. That factor aside, Blue-Eyes being able to summon multiple high attack monsters, having access to Treacherous Trap Hole, as well as having Sphere Kuriboh to prevent pushes for lethal are all factors that make it extremely difficult for Mermails to find a consistent way to break through boards. Atlantean Heavy Infantry is important to maximize to ensure that you have a destruction effect available. Moreover, having access to a copy of one of the Abyss Equip Spells allows Megalo to attack over any monster with its 3200 attack. Moreover, Concentrating Current is relevant to out boards of high attack monsters.
Spellbooks can be annoying without Sealed Tombs; however, with Sealed Tombs, Spellbooks become Mermail’s easiest matchup! Tombs opens up a lot of doors to counter fields of Silent Magician and Spellbook of Fate. The least resourceful way to out a turn 1 board of Silent Magician and Fate is to activate Sealed Tombs, summon Deep Sea Diva, and then use her effect to summon Atlantean Marksman. From there, you can Synchro summon into an Armades, Keeper of Boundaries, which will prevent Silent Magician from being able to special summon Silent Magician LV8. Moreover, you can summon Abyss Soldier, return it to the hand, and then use your other resources to go in for lethal. Sphere Kuriboh can help to ensure that Silent Magician LV8 does not generate havoc on your board. Moreover, Concentrating Current is a reasonable card to consider since it allows Mermail Abyssmegalo and Mermail Abyssteus to beat over Silent Magician LV8 and go for lethal if you have Mermail Abyssmegalo specifically.
Triamids are one of the harder matchups you can face without siding. Due to Triamids being able to swap out their Field Spell with their Triamid monsters on your turn, you are unable to do too much with Atlantean Heavy Infantry. Moreover, Triamid Kingolem prevents Mermail Abysslinde from floating. The best play you are able to make is using Abyss-sphere on their turn to summon Mermail Abysslinde, which in turn will allow you to discard Atlantean Heavy Infantry with a special summoned Mermail Abysspike. If you discard Atlantean Heavy Infantry on their turn, you will be able to destroy their cards, so it is “wise” to pop the Triamid player’s Field Spell. Cosmic Cyclone becomes a huge asset in the side deck since it will allow you to have more freedom with your Atlantean Heavy Infantry pops with Cosmic Cyclone being able to banish the Triamid Field Spell. Moreover, Concentrating Current can help push for lethal over 2 Triamid monsters with Mermail Abyssmegalo.
Koa’ki Meiru has started to decline in use after the Semi-Limit of Diamond Core of Koa'ki Meiru. By Semi-Limiting Diamond Core, the deck no longer has access to Treacherous Trap Hole, which is one of Mermails’ kryptonites. With Sealed Tombs, you are able to easily out Elemental HERO Brave Neos by discarding an Atlantean Heavy Infantry. Moreover, with Abyss-sphere, it becomes a lot more difficult for Koa’ki Meiru to push for lethal without having access to both Koa'ki Meiru Maximus and Koa'ki Meiru Ice on the field at the same time. If you have Atlantean Heavy Infantry in hand alongside Abyss-sphere, you can preemptively activate Sealed Tombs and set Abyss-sphere. This way, if the Koa’ki Meiru player tries to push for lethal, you will be able to stop the attack and then destroy one of their more threatening monsters on the field, whether that be Koa’ki Meiru Maximus or Elemental HERO Brave Neos. Having access to Sphere Kuriboh in the side is one of your greatest assets to helping survive against pushes for lethal against you.
Neos Cyberark can be a nuisance to deal with because you need to play around Destiny Draw while also looking for chances to push for lethal. Thankfully, this task is a lot easier with Sealed Tombs. Like the Koa’ki Meiru matchup, having access to Sealed Tombs allows you to play around the protection of Elemental HERO Brave Neos as well as Bacon Saver. Whether you use Mermail Abysspike or Mermail Abyssteus to send Infantry, both monsters are small enough to not activate the opposing player’s Destiny Draw. When trying to push for game, make sure you have attacked with one of those monsters first before trying to swing with Mermail Abyssmegalo. Mermail Abyssmegalo attacking directly without being in range of lethal will always be accepted by your opponent since it will allow them to use Destiny Draw on their turn. Concentrating Current is an excellent way to exploit this factor because it is likely that they will not activate Sphere Kuriboh so that they can get a Destiny Draw, which will allow you to win the game off of that one interaction. Be careful, however, as this transaction will not be accepted if Concentrating Current has been seen previously, so make sure to make the most of it when you use it. Abyss Soldier is another way to out Elemental HERO Brave Neos, as well as potentially return a Lava Golem if the card is burning too many LP. Sphere Kuriboh also helps by stopping a search from Elemental HERO Brave Neos, in addition to preventing Cyberdark Edge from literally edging your Life Points away while equipped with Cyberdark Cannon or Leng Ling.
Crystrons are in an interesting spot in the meta because the archetype is tier worthy, but it is still in the process of being optimized. Since the deck usually uses Treacherous Trap Hole and World Legacy Clash as their only defensive cards, as well as relying on Crystron Citree to Synchro summon on your turn, it is critical to use Sealed Tombs to have a decent shot against them. If Crystrons are not fortunate to see Treacherous Trap Hole, it can be somewhat easy to OTK them, so that is what you are going for during the turn you activate Sealed Tombs. Failure to win in that specific turn will usually allow Crystrons to come back and win the game. System Down is undoubtedly the strongest card to consider in the side deck since Crystrons are extremely reliant on the Graveyard. Moreover, Citree can only Synchro summon a Machine Synchro monster when special summoning on the opponent’s turn, so System Down reliably shuts down any play they could make. Abyss Soldier can also reliably out one Synchro on their field, which can in turn make it easier to apply pressure. Concentrating Current is
Magnets are an interesting matchup because they use defensive cards in Treacherous Trap Hole and Offerings to the Doomed. Pair that with their ability to make Valkyrion the Magna Warrior via the effect of Delta the Magnet Warrior, as well as the ability to easily make their boss monster Berserkion the Electromagna Warrior, and things can get difficult. In order to win this matchup, you will need to push earlyto push early so that they are unable to get an ideal setup. If you have Sealed Tombs, make sure to use it against Delta the Magnet Warrior with an established Graveyard to ensure that they will be unable to banish 3 Magnets for Valkyrion the Magna Warrior. Moreover, keeping Atlantean Heavy Infantry in hand can be handy in terms of dealing with Berserkion the Electromagna Warrior. Cosmic Cyclone is a strong option to consider to ensure their defensive cards will be unable to stop your push. Abyss Soldier is also not a terrible card to have handy to safely remove Valkyrion the Magna Warrior and Berserkion the Electromagna Warrior, but keep in mind that Magnets will likely have enough resources to summon one of those monsters again, so be sure to capitalize the turn you remove them.
Subterror is one of the hardest matchups to face; fortunately, they are less annoying to deal with now that the ability Masked Tribute is nerfed. This is the one match where Atlantean Marksman actually gets more value than Atlantean Heavy Infantry. It is critical to use Atlantan Marksman’s effect to destroy their set backrow, specifically Subterror Final Battle if they have revealed it. Usually, Atlantean Marksman will not destroy a set Spell/Trap card that is flipped face-up; however, since Subterror Final Battle gets flipped face-down after resolving, Atlantean Marksman will still destroy it. Failure to clear Subterror Final Battle while they control a Subterror Behemoth card will result in an inevitable loss. Once you have cleared their backrow, it is important to try and clear their monsters with your Synchros. Vermillion Dragon Mech and Gungnir, Dragon of the Ice Barrier are both amazing cards to clear threats like Subterror Behemoth Umastryx before it can ruin your field. Cosmic Cyclone is critical to play to ensure that you have another option to clear backrow if you do not open Atlantean Marksman. Moreover, it gives you more freedom with how you use your Atlantean Marksman if you do open it. Royal Command also makes this matchup a lot easier since Mermails are usually able to beat over high defence monsters, assuming an influx of them are not summoned.
Metaphys can be difficult to deal with since they have a few annoying tools in Metaphys Daedalus, which can remove all of your special summoned monsters, as well as Metaphys Dimension, which can remove a monster if they banish a Metaphys card. Moreover, Sealed Tombs does practically nothing against this deck. Fortunately, the deck can still do well against Metaphys, but there is more reliance on being able to push for lethal in one turn. Failure to win quickly against Metaphys will likely result in a loss. Cosmic Cyclone can help clear the way of Dimensions so that your monsters will not get banished by it. Moreover, Concentrating Current helps with pushing for lethal faster, especially if the Metaphys player is not using Grit as their ability.
Finally, we have reached the mirror match-up. As mentioned previously, Sealed Tombs only prevents the special summon of Mermail Abyssgunde, so it is more or less useless. Beatdown is the best ability to run for the mirror match, but since the deck is not going to show up often in tournaments, you are still better off playing Sealed Tombs, so I will in turn assume my opponent is also playing Sealed Tombs assuming he does not want to lose to half of the meta. In the classical build where both people are playing Abyss-sphere, the best play you can do against the mirror going first is set Abyss-sphere or Mermail Abysslinde. You generally want to be the second person to commit to a push since it is far easier to out your opponent’s established board with Atlantean Heavy Infantry. With that being said, you also want to make sure your opponent is unable to go for lethal against you. A rule of thumb is if you have Atlantean Heavy Infantry in hand and have a set Abyss-sphere or Mermail Abysslinde, you are better off waiting for your opponent to commit because you can always disrupt one of your opponent’s plays with Mermail Abysspike sending Atlantean Heavy Infantry. Once you have disrupted your opponent’s push, it is generally safe to go in and push yourself since your opponent has less resources to defend. If you succeed in outing your opponent’s push, you will likely win the game since Mermail Atlanteans are extremely reliant on having at least 2 cards to work with to generate plays. Treacherous Trap Hole in the mirror is not extremely common, but when present, it is a card that can generate huge momentum for the person who resolves it. For that very reason, it is not a terrible idea to consider playing 1 Abyss-scale of Cetus. Cetus serves the purpose of both negating an Abyss-sphere or Treacherous Trap Hole, as well as being able to attack over your opponent’s Mermail Abyssmegalo or Mermail Abyssteus with one of your own. Concentrating Current is another fantastic card to play in the mirror to ensure your push goes through. In addition, Sphere Kuriboh being able to stop an opposing Mermail Abyssmegalo from attacking twice is huge.
Mermail Atlanteans are a fun, strong deck that may still lack certain tools to be a tier deck in the current meta, but is nonetheless a sleeper deck that has the potential to beat everything. Furthermore, since the deck is not Tier, the deck does not have a huge margin for error; it must be played with precision to succeed. Mermail Atlanteans are my favourite deck that Duel Links has released, and I will continue to play them, regardless of their actual relevance in the metagame because the deck is coherent enough to reach King of Games consistently. Moreover, this deck can only become stronger with the future release of XYZs.
-Shoutout to my Team War team Phoenix for giving me a chance to play on a team of their caliber. It is because of my teammates on Phoenix that my love for competitive Duel Links flourished and motivated me to become the best Duel Links player I can be. We are out to win this season for Team Wars after falling short in top 4 last season, but we are also a family outside of clapping teams, so it would be a crime to not mention them first.
-Shoutout to my Clan War team Faceless Duelists for also giving me a chance to play on their team this season. Much like Team Phoenix, Faceless Duelists are also a team of clappers that are also family to me, so I owe part of my success to them as well. #SeasonFD
-Shoutout to Wise for for both providing insight on various matchups (specially Triamids, Blue-Eyes, Spellbooks, and Magnets), as well as taking the time to review my guide after it was all written. I also want to mention that at the time of this shoutout, Wise has had the most success with Mermail Atlanteans, boasting an astounding record of 12-2 for games with 6 match wins in 2 weeks of Clan Wars. I have learned a lot from him, and I am sure he would be glad to help any of you out if you have further questions about the deck (His list is being kept on the down low though, so refrain from asking him that. His list will be posted at some point in the near future!).
-Shoutout to INVICTVS for giving me access to Mermail Atlanteans in its entirety. Without him, I would be in greater debt as a University student, so him getting the deck for me to actually playtest on Duel Links as opposed to just DuelingBook means the world to me.
-Shoutout to Turboman for actively responding in the Mermail Atlantean chat while I am away. He was initially going to do the guide with me, but then I ended up doing the whole thing myself (oops). Regardless, I appreciate everything that he has done in the Duel Links Meta community for that topic.
-Shoutout to LogicJones for actively pursuing different strategies with Mermail Atlanteans, regardless of how relevant they actually are. Your passion for the deck has not gone unnoticed, so keep up the good work!
-Shoutout to RandomPl0x for formatting the guide as well as being generous to me throughout the process of making it. I appreciate you and everything you do for Duel Links Meta!
-Shoutout to the rest of the people that I missed, but still actively help the Mermail Atlantean channel grow. We may not be tier, but the Duel Links Meta community is something I cherish. I love the debates and discussion we have about the deck, so thank you for making the Mermail Atlantean chat relevant and fun (Sealed Tombs > Beatdown, don’t @ me kappa).