Core Mermail Atlantean

Abyssrhine, the Atlantean Spirit - ROTA-EN017 - Secret Rare

(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.

Mermail Shadow Squad - ROTA-EN018 - Ultra Rare

(This card is always treated as an "Atlantean" card.)
You can discard 1 card to the GY; WATER monsters you currently control become Level 7 until the end of this turn. If this card is sent to the GY to activate a WATER monster's effect: Special Summon 1 Level 4 or lower "Atlantean" or "Mermail" monster from your Deck, except "Mermail Shadow Squad", also you cannot Special Summon from the Extra Deck for the rest of this turn, except WATER monsters. You can only use each effect of "Mermail Shadow Squad" once per turn.

Neptabyss, the Atlantean Prince - RA03-EN013 - Super Rare

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.

Atlantean Dragoons - RA03-EN006 - Super Rare

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".

Mermail Abysspike - RA04-EN012 - Super Rare

Mermail Abyssteus - RA03-EN007 - Super Rare

You can discard 1 other WATER monster to the GY; Special Summon this card from your hand. When Summoned this way: You can add 1 Level 4 or lower "Mermail" monster from your Deck to your hand. You can only use this effect of "Mermail Abyssteus" once per turn.

Atlantean Heavy Infantry - RA04-EN010 - Super Rare

Abyss-sting Triaina - ROTA-EN062 - Common

Special Summon 1 "Atlantean" or "Mermail" monster from your hand or GY, and if you do, equip it with this card. If the equipped monster would be destroyed by battle or card effect, you can send this card to the GY instead. You can banish this card from your GY, then target up to 3 of your Fish, Sea Serpent, and/or Aqua monsters that are banished or in your GY; shuffle them into the Deck. You can only use this effect of "Abyss-sting Triaina" once per turn. You can only activate 1 "Abyss-sting Triaina" per turn.

Poseidra Abyss, the Atlantean Dragon Lord - ROTA-EN043 - Ultra Rare

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.

Mermail Abyssgaios - RA04-EN065 - Super Rare

Abysstrite, the Atlantean Spirit - SUDA-EN046 - Super Rare

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.

Mermail King - Neptabyss - ROTA-EN046 - Ultra Rare

2+ monsters, including a Fish, Sea Serpent, or Aqua monster
Your opponent cannot target WATER monsters this card points to with card effects. You can only use each of the following effects of "Mermail King - Neptabyss" once per turn. If a WATER monster(s) is sent to the GY to activate a card or effect (except during the Damage Step): You can take 1 "Abyss-" Equip Spell from your Deck or GY and either add it to your hand or equip it to this card. If this card in its owner's possession is destroyed by an opponent's card: You can add 1 "Atlantean" or "Mermail" monster from your Deck to your hand.

Mermail Abyssalacia - MP20-EN095 - Super Rare