Wikia

In keeping with the general theme of the "Six Samurai", the "spy" on the card is disguised as a Feudal Japanese peasant. Traveling peasants and merchants were often used during Japan's Feudal period by warlords to check on opposing factions' territories by crossing into them before returning ,just as this card's effect has a monster only temporarily "joining" the opposing side.
- The expression on the merchant's face also matches with that of "Hand of the Six Samurai", who effectively symbolizes an assassin via its effect.

Card Trivia:Shien's Spy