Wendy Sato serves as a member of the High Card organization, working within the accounting and clerical staff at the Pinochle car company's Old Maid branch.

She is beautiful yet unfriendly, often serious, a temperament which leads to frustration with the working methods of colleagues such as Finn and Chris. She holds a strong enjoyment of eating and drinking, more than any other High Card member, and consuming alcohol greatly improves her mood, shifting her usual cold demeanor into a far sunnier one.

Her membership in High Card was arranged through connections from her father, a master swordsman.

She wields the Ace of Spades X-Playing Card, 《Love and Peace》, which grants her a powerful sword. The card's ability can be used without fully drawing the blade, though doing so unlocks significantly greater power. A major drawback accompanies this enhanced state: she becomes overtaken by a separate personality known as Love-P, or LAP, which is intent solely on killing everyone nearby. The only way for her to return to normal is for the sword to be physically removed from her grasp.