"As I bear the darkness into battle, my suffering becomes my strength."
While Final Fantasy X is focused on and narrated by Tidus, Yuna is the central character in terms of the purpose of the main characters' journey. All of Yuna's fellow travelers come along solely to guard her on her quest to bring back a period of peace to her world. Yuna's name means, in different regions of Japan, both "night" and "blossom" and also refers to a hibiscus flower that blooms at night; this is symbolic of Yuna freeing the world of Spira from a time of pain.
The daughter of High Summoner Braska, Yuna's journey follows her father's footsteps in trying to rid Spira from the death surrounding the seemingly eternal monstrosity known as Sin. Ten years prior to the start of the game, her father defeated Sin, but Spira accepts that every ten years Sin returns after being defeated. In order to defeat Sin and bring those ten years of calm back to Spira, Yuna must go on a pilgrimage to visit every temple in Spira and gain new Aeons: powerful creatures born of the spirits of certain deceased people. She meets Tidus when he washes up on the shore of her home island, and she asks him to become her guardian on her pilgrimage.