Between the Heart and Lungs

Summoners are not supposed to care for aeons. Aeons are tools to be used, to serve the will of the Summoner. So say the teachings of Yevon. Yuna's first step on the path of heresy is the first time she thinks of an aeon as a person, and lets them in much deeper than any summoner is supposed to allow. Yuna/Aeons, soul ecstasy/sex, exploration of Spiran culture and society.