[Now that I think about it, this guy stole my nickname!] Yuel grumped. [I remember trying to choose "Rook" as an IGN but it was already taken. Because of that, I got stuck with a needlessly bombastic nickname like Chessmaster. This is all Cato's fault!]
Rook was foreshadowed when they were choosing the names in the first year
Rook was the leader of the Leopards, and most likely their shot-caller. So, judging by the defensive formation the Leopards employed, this shot-caller clearly liked defensive strategies.