Atlantean

"Atlantean", known as "Sea Emperor" ( Kaiō) in Japan, is an archetype of WATER Sea Serpent-Type monsters. They were first introduced in Phantom Darkness, with "Atlantean Pikeman". They later gained more members in Return of the Duelist, "Structure Deck: Realm of the Sea Emperor", which also introduced their first support card, "Atlantean Marksman", and "Lord of the Tachyon Galaxy" which introduced "Atlantean Tridon".

Playing Style
The focus of this archetype is to swarm the field with Level 3 or lower WATER monsters with the effects of "Atlantean Marksman", "Deep Sea Diva" and "Atlantean Heavy Infantry" to later Tribute them for the summon of their ace monster, "Poseidra, the Atlantean Dragon", or to Synchro Summon with "Deep Sea Diva" and "Genex Controller", preferably the "Ice Barrier" Synchro Monsters.

Also, the effects of "Atlantean Marksman", "Atlantean Heavy Infantry" and "Atlantean Dragoons" trigger when they are sent to the Graveyard as cost for a WATER monster's effect, so cards like "Abyss Soldier" and "Gungnir, Dragon of the Ice Barrier" would be a good add to the Deck.

"Atlantean" effects also activate if they are detached from an Xyz Monster (the effect only requires the monster to be sent to the Graveyard, like "Dandylion"), so a great addition to this deck are WATER Xyz Monsters, like "Number 17: Leviathan Dragon". Here is a list of WATER Xyz Monsters that can Trigger the effects of the "Atlantean" (note that all current "Atlantean" that share this effect are Level 2, 3 or 4. However, you can use cards like "Lemuria, the Forgotten City" for Xyz Summoning some of these higher Rank monsters):

The Spell Card of this archetype, "Call of the Atlanteans", allows you to Summon 3 Level 3 or lower Sea Serpent-Type monsters from your Graveyard, but you can't Special Summon the turn it is activated, and there must be at least 3 acceptable monsters in your Graveyard. Since most of the effects of "Atlantean" activate when they are sent to the Graveyard, the latter shouldn't be so hard, but cards like "Skreech" can help you dump cards. "Call of the Atlanteans" is a Quick-Play Spell Card, you can activate it during your opponent's End Phase, so you can Special Summon normally in your turn, as long as it was set before.

"Atlantean" Decks run cards that clean the field before attacking. "Genex Undine" can destroy any card your opponent controls by sending either "Atlantean Marksman" or "Atlantean Heavy Infantry" from you Deck to the Graveyard, while adding a "Genex Controller" (a Level 3 Tuner) to your hand. "Abyss Soldier" and "Abyss Warrior" can trigger the effect of the "Atlantean" monsters while returning a monster to the hand and a card in the Graveyard to the top or bottom of the Deck, respectively.

This archetype also goes hand-in-hand with the "Mermail" archetype since most of the Mermails effects involve discarding a water monster as a cost which will in turn activate the Atlantean's effects. By using "Mermail Abysspike," "Mermail Abyssturge", and/or "Mermail Abyssmegalo" with the "Atlanteans" you will be able to activate their useful effects and the "Atlanteans" effects together.

One of the great support cards for this Deck, "Deep Sea Diva", can Special Summon any low-Level "Atlantean" monster from your Deck. If you choose to summon Atlantean Marksman, every time you inflict battle damage to your opponent, you can Special Summon another "Atlantean" monster from your deck, like "Atlantean Attack Squad" for a beatstick, while also having monsters for a Rank 3 Xyz monsters, or Synchro material for Level 4 Synchro Monsters or above. Also you can special summon "Atlantean Heavy Infantry" with her effect which will allow you to normal summon an extra sea-serpent type monster like "Atlantean Marksman," "Atlantean Dragoons," or best of all another "Deep Sea Diva."

There are many choices for Synchro Monsters. You can go for "Ally of Justice Catastor" (Diva + Marksman or Assaultman), "Gungnir, Dragon of the Ice Barrier" (Diva + Armed Soldier + Marksman) and any other of your choice. The "Ice Barrier" Dragons discard cards to activate their effects, which clean the field by themselves. Brionac can return any card on the field to the hand any number of times in your turn, so you can use its effect to return one Atlantean monster in your field, then discard it to return another one to the hand, and since it was discarded, its effect activates.

Use "Atlantean" monsters in combination with "Koa'ki Meiru Ice". "Koa'ki Meiru Ice" will be a 1900 beater that allows you to destroy, multiple times during the same turn, a Special Summoned monster and a Set or face-up card depending on what "Atlantean" you pay for the cost with. To keep your "Koa'ki Meiru Ice" alive, you will need to have a "Iron Core of Koa'ki Meiru" or a Continuous Spell Card in your hand. A recommended Continuous Spell Card could be "D.D. Trench" or "Water Hazard".

A card that you can use with "Atlanteans" is "Raging Eria" due to her cost of tributing a WATER monster to activate her effect. You can tribute cards like "Atlantean Marksman" or "Atlantean Heavy Infantry" to special summon a WATER monster from your hand while destroying a card your opponent controls. You can also tribute "Atlantean Dragoons" to special summon a WATER monster while adding a sea serpent monster from your deck to your hand. "Raging Eria" can also help with summoning high level monsters easier like "Poseidra, the Atlantean Dragon" or even "White Night Dragon", a powerful WATER monster.

There is a loop you can do if you get Dewloren, Tiger King of the Ice Barrier and Gungnir, Dragon of the Ice Barrier on the field with a Deep Sea Diva in your hand. Summon the Diva, SS Atlantean Heavy Infantry or Atlantean Marksman, bounce Diva and the Atlantean, discard the Atlantean with Gungnir, repeat next turn. This leaves you with Dewloren at 3000 ATK, and your opponent's field wiped by Gungnir and the discarded Atlantean. Without the diva you can use Surface or Call of the Atlanteans, SS the monster(s) that fit your need, then bounce the monster(s) with Dewloren, and discard it with Gungnir.

Through use of A Legendary Ocean, it is possible to use the Atlantean Dragoons effect to attack directly with it and any level 4 sea serpents. Through this, you can also allow Atlantean Marksman to do battle damage unhindered by the opposing monsters, getting out Atlantean Attack Squad and dealing another substantial blow to the opponents life points. Also, because of the lowered levels, all non-tribute atlantean monsters are protected by Aegis of the Ocean Dragon Lord, allowing this to take place on multiple turns without worry of cards like Mirror Force

Another great card for the deck is Cold Enchanter, which can be used for a massive damage card. Also since it's effect can be activated multiple times per turn, it works amazingly with Snowdust Giant an amazingly powerful xyz monster for the deck. You simply detach one material from Snowdust Giant and reveal the atlanteans you are going to discard with Cold Enchanter then distribute the counters among the two monsters, you then discard the very atlanteans you revealed for the effect of Snowdust Giant through the effect of Cold Enchanter to increase her attack largely and decrease your opponents attack massively.

Monsters

 * Poseidra the Atlantean Dragon(x2)
 * Atlantean Tridon
 * Atlantean Dragoons(x2)
 * Atlantean Attack Squad(x2)
 * Atlantean Heavy Infantry(x2)
 * Atlantean Marksman(x2)
 * Abyss Soldier
 * Abyss Warrior
 * Deep Sea Diva(x2)
 * Hammer Shark
 * Shark Stickers
 * Lost Blue Breaker
 * Spined Gillman(x3)
 * Double Shark
 * Mermail Abyssturge
 * Mermail Abysslung
 * Snowman Eater(x2)
 * Cold Enchanter(x2)

Spells

 * Call of the Atlanteans
 * Salvage(x2)
 * Surface
 * Moray of Greed(x2)
 * A Legendary Ocean(x3)
 * Pot of Avarice

Traps

 * Aegis of the Ocean Dragon Lord
 * Bubble Bringer
 * Call of the Haunted
 * Fiendish Chain
 * Safe Zone
 * Aquamirror Cycle
 * Spiritual Water Art - Aoi
 * Dimensional Prison

Extra Deck

 * Snowdust Giant
 * Bahamut Shark
 * Number 17: Leviathan Dragon
 * Evigishki Merrowgeist
 * Scrap Dragon
 * Number 20: Giga-Brilliant
 * Daigusto Phoenix
 * Gachi Gachi Gantetsu
 * Dewloren, Tiger King of the Ice Barrier
 * Gungnir, Dragon of the Ice Barrier
 * Armory Arm
 * Hydro Genex
 * Sea Dragon Lord Gishilnodon
 * T.G. Hyper Librarian
 * Mist Wurm
 * Stardust Dragon

Atlantean OTK
This OTK focuses on using "Mermail Abyssmegalo's" double attack ability to deal massive damage.

What you need:
 * Mermail Abyssmegalo (Hand)
 * Deep Sea Diva (Hand)
 * 2 WATER Monsters (Hand)
 * 1 Level 3 Sea Serpent-Type Monster (Hand)


 * Atlantean Heavy Infantry (Main Deck)
 * Abyss-scale of the Kraken (Main Deck)
 * Sea Dragon Lord Gishilnodon (Extra Deck)

How it Works:
 * Discard 2 WATER monsters to Special Summon "Mermail Abyssmegalo" with his effect (make sure you keep a Level 3 Sea Serpent in your hand).
 * Because you summoned "Abyssmegalo" using its own effect you can add "Abyss-scale of the Kraken" to your hand. Equip it to "Abyssmegalo".
 * Normal Summon "Deep Sea Diva", use her effect to Special Summon "Atlantean Heavy Infantry" from your Deck in Attack Position.
 * Use "Heavy Infantry's" ability to normal summon the Level 3 Sea Serpent from your hand.
 * Synchro Summon "Sea Dragon Lord Gishilnodon" using "Deep Sea Diva" and the Level 3 Sea Serpent.
 * Tribute "Heavy Infantry" to allow "Abyssmegalo" to attack twice. This also activates "Gishilnodon's" effect and increases its attack to 3000, and "Heavy Infantry's" effect to destroy a face-up card your opponent controls.
 * Attack with both: 5600 (Abyssmegalo x2) + 3000 (Gishilnodon) = 8600

Atlantean OTK (Simpler Version)
What you will need.
 * "Mermail Abyssmegalo" (Hand)
 * 2 WATER Monsters (Hand)
 * 1 "Deep Sea Diva" (Hand)


 * "Atlantean Heavy Infantry" (Main Deck)
 * "Atlantean Attack Squad" or "Atlantean Dragoons" (Main Deck)

How to Pull it off.
 * Special Summon "Mermail Abyssmegalo" by Discarding 2 WATER monsters. Search for any "Abyss-scale" if you want.
 * Normal Summon "Deep Sea Diva", and Special summon "Atlantean Marksman" with her effect.
 * Use "Abyssmegalo's" effect and Tribute "Diva", then attack using the "Marksman", and Special Summon an "Atlantean Attack Squad" or "Atlantean Dragoons" from your Deck.
 * Then, attack with "Abyssmegalo" for 4800 damage, and your other Atlantean for 2200 or 1800. Including the 1400 for "Marksman" you at least 8000 damage.