- "Ah, of course. 'Protect the summoner, even at the cost of one's life'. The Code of the Guardian."
- —Seymour Guado
In Final Fantasy X, a guardian is a warrior tasked with protecting a Summoner during their pilgrimage across Spira to defeat Sin and bring the Calm. Most summoners traveled with one or two guardians, though some, most notably Yuna, were protected by upwards of six.
The earliest known guardian, as well as the first to defeat Sin, was Lord Zaon, the lone guardian of Lady Yunalesca, the first High Summoner. Another duty of the guardian was to offer themselves during the final summoning to calm Sin and ultimately become the new one, although it would seem this was unknown to the summoners and their guardians prior to their potential meeting of Yunalesca.
Guardians are the only individuals allowed to accompany a summoner into a Chamber of the Fayth. If anyone else does so, then the summoner may face sanctions as strong as excommunication from Yevon, even if they did so without the summoner's knowledge or consent.