Final fantasy advent children what yazoo mean by pions?

What he means is people at TURKS and Shin-Ra, the people at Shin-Ra gave information about jenova, but later in the movie it revealed that they won't allow Kadaj gang to get jenova. Square-Enix encourage people to play the original FF7 game, the expansion of the game (Dirge of Cerberus), and watch the anime (Before Crisis), so you can know the whole story... What a marketing trick i say :D