Abyssrhine, the Atlantean Spirit
Level 3 WATER/Aqua Effect1600 ATK / 1600 DEF
(This card is always treated as a "Mermail" card.)
You can Tribute this card from your hand and 1 "Atlantean" or "Mermail" monster from your hand or field; take 1 Level 7 Fish, Sea Serpent, or Aqua monster from your Deck and either add it to your hand or Special Summon it, also you cannot Special Summon from the Extra Deck for the rest of this turn, except WATER monsters. During your opponent's turn (Quick Effect): You can banish this card from your GY and discard 1 card to the GY; draw 1 card. You can only use each effect of "Abyssrhine, the Atlantean Spirit" once per turn.
Abysstrite, the Atlantean Spirit
Level 7 WATER/Sea Serpent Xyz Effect2100 ATK / 2800 DEF
2+ Level 7 WATER monsters
WATER monsters you control gain 300 ATK/DEF for each material attached to this card. You can only use each of the following effects of "Abysstrite, the Atlantean Spirit" once per turn. If this card is Xyz Summoned: You can target 1 Level 7 or lower Fish, Sea Serpent, or Aqua monster in your GY; Special Summon it. You can detach 1 material from this card; Set 1 "Abyss-" Trap from your Deck.
Atlantean Attack Squad
Level 3 WATER/Sea Serpent Effect1400 ATK / 0 DEF
This card gains 800 ATK while you control a face-up Fish, Sea Serpent, or Aqua-Type monster other than this card.
Atlantean Dragoons 40
Level 4 WATER/Sea Serpent Effect1800 ATK / 0 DEF
All Level 3 or lower Sea Serpent-Type monsters you control can attack your opponent directly. When this card is sent to the Graveyard to activate a WATER monster's effect: Add 1 Sea Serpent-Type monster from your Deck to your hand, except "Atlantean Dragoons".
Atlantean Heavy Infantry
Level 2 WATER/Sea Serpent Effect0 ATK / 1600 DEF
During your Main Phase, you can Normal Summon 1 Level 4 or lower Sea Serpent-Type monster in addition to your Normal Summon/Set. (You can only gain this effect once per turn.) When this card is sent to the Graveyard to activate a WATER monster's effect: Target 1 face-up card your opponent controls; destroy that target.
Atlantean Marksman
Level 3 WATER/Sea Serpent Effect1400 ATK / 0 DEF
When this card inflicts battle damage to your opponent: You can Special Summon 1 Level 4 or lower "Atlantean" Sea Serpent-Type monster from your Deck, except "Atlantean Marksman". When this card is sent to the Graveyard to activate a WATER monster's effect: Target 1 Set card your opponent controls; destroy that target.
Atlantean Pikeman
Level 2 WATER/Sea Serpent Normal1400 ATK / 0 DEF
The Great Ocean Lord, who reigns over the depths, is served by these lancers. Deep-sea creatures exist in fear of facing the stream of attacks their lances are capable of.
Call of the Atlanteans
Quick-Play SpellTarget 3 Level 3 or lower Sea Serpent-Type monsters in your Graveyard; Special Summon all 3 of them. You cannot Special Summon any other monsters during the turn you activate this card.
Legendary Atlantean Tridon
Level 3 WATER/Sea Serpent Effect1600 ATK / 800 DEF
You can Tribute this card and 1 Sea Serpent-Type monster; Special Summon 1 "Poseidra, the Atlantean Dragon" from your hand or Deck, then all monsters your opponent currently controls lose 300 ATK.
Neptabyss, the Atlantean Prince 33
Level 1 WATER/Sea Serpent Effect800 ATK / 0 DEF
You can send 1 "Atlantean" monster from your Deck to the Graveyard, except "Neptabyss, the Atlantean Prince"; add 1 "Atlantean" card from your Deck to your hand, except "Neptabyss, the Atlantean Prince". If this card is sent to the Graveyard to activate a WATER monster's effect: Target 1 "Atlantean" monster in your Graveyard, except "Neptabyss, the Atlantean Prince"; Special Summon it. You can only use each effect of "Neptabyss, the Atlantean Prince" once per turn.
Poseidra Abyss, the Atlantean Dragon Lord
Level 7 WATER/Sea Serpent Xyz Effect3000 ATK / 1800 DEF
3 Level 7 monsters
Once per turn, you can also Xyz Summon "Poseidra Abyss, the Atlantean Dragon Lord" by using 1 "Atlantean" or "Mermail" Xyz Monster you control. (Transfer its materials to this card.) Once per turn: You can detach 2 materials from this card, then send 1 WATER monster from your hand or Deck to the GY; return up to 3 cards your opponent controls to the hand. If this Xyz Summoned card is sent to the GY: You can discard 1 card to the GY; Special Summon 3 Level 3 or lower Fish, Sea Serpent, and/or Aqua monsters from your hand and/or GY.
Poseidra, the Atlantean Dragon
Level 7 WATER/Sea Serpent Effect2800 ATK / 1600 DEF
You can Tribute 3 Level 3 or lower WATER monsters; Special Summon this card from your hand or Graveyard. When you do: Return all Spell and Trap Cards on the field to the hand, and if you do, if 3 or more cards are returned to the hand by this effect, all monsters your opponent currently controls lose 300 ATK for each.
Poseidra, the Storming Atlantean
Level 7 WATER/Sea Serpent Effect2800 ATK / 1600 DEF
While you control a monster, except "Poseidra, the Storming Atlantean", your opponent's monsters cannot target this card for attacks. You can only use each of the following effects of "Poseidra, the Storming Atlantean" once per turn. You can send 1 other WATER monster from your hand or face-up field to the GY; Special Summon this card from your hand. If this card is Normal or Special Summoned: You can send 1 "Atlantean" or "Mermail" monster from your Deck to the GY, then target 1 card your opponent controls; return it to the hand.