The epic plot of Final Fantasy X derives, like many other fantasy stories, from tropes refined and popularized by Tolkien (its band of diverse peoples journeying a great distance to destroy evil echoes Tolkien’s Fellowship, and specific plot elements such as ancient heroes reemerging as evil henchmen are also reminiscent of the Rings trilogy) and its characters are similarly inspired. Though Tidus is the story’s central character, his role in the journey is as one of several protectors for Yuna, who has the magical powers necessary to defeat Sin when the time comes. She has picked up the journey in honor of her father, who was responsible for Sin’s defeat during his last rampage.
Yuna is presented as determined and resolved, with a tendency toward melancholy. The reasons for this become clear later when it is revealed that successfully engaging Sin inherently brings about the death of the summoner who challenges it—just as Frodo’s quest to destroy the ring ultimately doomed him as well in Tolkien’s story—and that Yuna’s decision early in her life to pursue this goal meant resigning herself to that fate.
Tidus is not the only one who tries to dissuade Yuna from her path, once he finds out the truth. The religious leader Seymour also makes attempts at various points in the game to stop Yuna from defeating Sin, initially by offering his hand in marriage and later, more directly, by issuing a death warrant on her from the church. He is smooth and devious until his plans fall apart, at which point he unhesitatingly turns to force to achieve his ends.
Between the three of them, they fall squarely into Scholes’ categories of "beauty and ugliness, goodness and badness," but this is no obstacle toward their status as believable and well-drawn characters.