In Never Let Me Go, what is the significance of the imaginary game Kathy H. plays with Ruth?

Ruth
has an expressive, dominant personality that comes out throughout the novel. Kathy is passive,
the follower of the pair, and defers to Ruth's leadership at every turn. We're introduced to
their dynamic in Chapter Four when Ruth strong-arms Kathy into playing a make-believe
game.

Ruth dispenses of the other girls who are playing with Kathy and
insists Kathy play only with her. She explains the many rules of the game she has made up and
becomes upset when Kathy doesn't follow the rules exactly as Ruth likes them followed. When Ruth
lashes out at Kathy and insists Kathy "clean-up" their pretend game, Kathy does so
willingly.

This dynamic follows the girls into adolescence and is most
evident when it comes to their relationship with Tommy. Kathy experiences deep feelings for him,
which are brushed aside when Ruth announces her intentions. Ruth spends much of their later
years bossing Kathy around, which comes to a head when they are adults and begin to fight more
often. Later, Kathy...