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.
Special Summons level 4 or lower “Atlantean” monster from your Deck to the Field, each time this card inflicts battle damage to your opponent.
If this card was discarded to activate another WATER monster’s effect, you can destroy 1 set card your opponent controls, including set monsters.
Weak ATK stats and has no DEF stats.
Although Atlantean monsters have good card removal effects, their ATK power generally is too weak to go over the stats threshold in the current meta, therefore they can be challenging to use in the current meta.
You can also opt to discard Atlantean monsters to trigger Abyss Soldier’s effect, as it can return 1 monster your opponent controls back to their hand, potentially clearing the way for your attack.
Atlantean Marksman allows you to Special Summon 1 Level 4 or lower "Atlantean" Sea Serpent-Type monster from your Deck, except "Atlantean Marksman", when it inflicts battle damage to your opponent.Additionally if this card was sent to the Graveyard to activate a WATER monster's effect, you can target 1 Set card your opponent controls and destroy it.
Atlantean Heavy Infantry allows you to 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, you can target 1 face-up card your opponent controls and destroy it. Atlantean Attack Squad is a 1400 ATK beater that increases its ATK by 800 if you control other face-up Fish, Sea Serpent or Aqua type monsters.
These “Mermail” monsters have effects that allows you to discard WATER monsters, in order to trigger their respective effects, which goes very well with “Atlantean” monsters since they can activate their effects when they were discarded to the Graveyard.