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Some major Sea Serpent-Type monsters include "Levia-Dragon - Daedalus", "Ocean Dragon Lord - Neo-Daedalus", "Orca Mega-Fortress of Darkness", "Bahamut Shark", "Brionac, Dragon of the Ice Barrier", "Sea Dragon Lord Gishilnodon", "Lavalval Chain", "Water Dragon", "Deep Sea Diva", "Moulinglacia the Elemental Lord", "Number 32: Shark Drake", "Abyss Dweller", "Mermail Abyssmegalo", and "Poseidra, the Atlantean Dragon".
In the early stages of the game, Sea Serpent-Type monsters and Fish-Type monsters acted as a pair, with Fish-Type monsters being weaker lower-Level monsters, and Sea Serpent-Type monsters being the more powerful higher-Level monsters. (This is equivalent to the old relationship between Dinosaur-Type monsters and Reptile-Type monsters).
Prior to the release of Raging Battle , the only support card Sea Serpent-Type monsters had was "Umi" (which was later replaced in usage by "A Legendary Ocean", which does not support them). Raging Battle introduced the Sea Serpent support cards "Spined Gillman", "Mermaid Archer" and "Deep Sea Diva", with the latter being the first card to exclusively support Sea Serpents. In contrast to early Sea Serpents, which were generally very strong high-Level monsters, the new Sea Serpents and their support focus on low-Level monsters and swarming, which allows for a viable Sea Serpent-based Deck.
In Photon Shockwave and Generation Force, additional support was introduced for Sea Serpent-Type monsters, including "Shark Stickers", "Fish and Kicks", and "Oh F!sh!". After Realm of the Sea Emperor and Abyss Rising, Sea Serpent-Type monsters became competitive with the creation of the "Merlantean" Deck.
- There are very few non-WATER Sea-Serpent-Type monsters.
- "Lavalval Chain" is the only Sea Serpent-Type monster to be Forbidden.