Structure Deck: Roar of the Sea Emperor is a Structure Deck in the Yu-Gi-Oh! Official Card Game (OCG). It is the twenty-third deck in the OCG's Structure Deck series (thirty-first including the Character Structure Decks), following Structure Deck: Dragonic Legion. The TCG equivalent of this deck is Structure Deck: Realm of the Sea Emperor.
The deck features around the WATER and Sea Serpent Theme. It includes many reprints, as well as introduces support for the "Atlantean" archetype.
Each Structure Deck: Roar of the Sea Emperor contains 40 cards in total. The number of card of each rarity are as follows: