Kairyu-Shin (archetype)
"Kairyu-Shin", known as "Leviathan" (リバイアサン Ribaiasan) in the OCG, is an archetype of WATER Sea Serpent monsters and Spell/Trap Cards. It originally made its debut with the card "Kairyu-Shin", released in Booster 6 in the OCG and Speed Duel: Trials of the Kingdom in the TCG, but only received its first support in Duelist Pack: Duelists of the Abyss / Legendary Duelists: Duels From the Deep. It is related to the Umi series.