Card Trivia:Poseidra, the Atlantean Dragon
- This is the cover card of Structure Deck: Roar of the Sea Emperor/Realm of the Sea Emperor Structure Deck.
- This monster appears in the artworks of "Call of the Atlanteans", "High Tide on Fire Island", "Phantasm Spiral Assault", and "Phantasm Spiral Crash".
- This monster's neck bracelet of this monster appears in the artwork of "Abyss-squall" and as an armband in the artwork of "Mermail Abyssgaios".
- According to Master Guide 4, this monster transforms into "Abyssgaios" with the magic of the armband.
- This is supported by how both the bottom of "Abyssgaio's" body resembles this monster, both of whom share the same Attribute (WATER), original ATK and DEF (2800/1600), and number of "stars" (7).
- This monster's neck bracelet of this monster appears in the artwork of "Abyss-squall" and as an armband in the artwork of "Mermail Abyssgaios".
- The tower appearing in the artwork of "A Legendary Ocean" appears in this card's artwork, albeit slightly visible in the upper left corner.
- Fittingly, the above-mentioned card's Japanese name is "Atlantis, the Legendary City", which likely serves as the home of the "Atlantean" monsters.
- This card is named after Poseidon, the Greek god of the sea who is often depicted wielding his signature weapon, the trident.
- Fittingly, this monster's three-pronged tail resembles the image of Poseidon's trident, a three-pronged spear used for spear fishing or as a polearm.
- This monster has a younger counterpart: "Legendary Atlantean Tridon".
- This card's original ATK (2800) is a combination of the 1400 ATK of "Atlantean Attack Squad" and "Atlantean Marksman", while its original DEF (1600) is based just on the 1600 DEF of "Atlantean Heavy Infantry", which are valid monsters to Tribute and Special Summon it.
- Fittingly, this card and the last two mentioned monsters debuted in Structure Deck: Roar of the Sea Emperor/Realm of the Sea Emperor Structure Deck, while "Attack Squad" was likely released as a teaser in the Return of the Duelist Core Booster pack two months prior.
