Seers must not change history to save themselves.
The Farseer tribe is the oldest known tribe on Gran Pulse, introduced in Final Fantasy XIII-2. Unlike the other residents of Gran Pulse, the Farseers worship Etro as their patron goddess and were able to survive the calamity caused by the War of Transgression. According to Captain Cryptic's Confounding Quiz, there was a Farseer legend where they had the power to turn people into l'Cie, but it has not been passed down for generations.
Centuries in the past on Gran Pulse, a people known as the Farseers built the prosperous city of Paddra. They flourished under the guidance of the seeress, whose predictions of the future guided the growth of their civilization.
After the War of Transgression that took place between Cocoon and Pulse, it is thought that the Farseer civilization died out. Another theory suggests that the people of Paddra became a nomadic tribe, and still roam the wilds of Gran Pulse.
In every generation, an identical girl is born with the "Eyes of Etro", an ability bestowed upon her by Etro which allows her to see into the future. The girl is always named "Yeul", and although she could see visions of the future, she would do nothing to change it, as it could bring catastrophe upon humanity. Yeul would store her visions in a device known as the Oracle Drive, and they would become known as prophecies. Final Fantasy XIII-2 Fragments After reveals that another law the Farseers lived by was to not allow the existence of paradoxes in time.
In the oldest Farseer tribe of ancient city of Paddra in the Yaschas Massif, Yeul was a respected leader and was protected by her Guardian, one of many warriors marked by a Pulse fal'Cie with the Focus to protect Yeul.
One notable Guardian was Gorgyra, a girl who chose to become Yeul's guardian. She was once fooled and in turn, the seeress's life was put in danger. Although Yeul forgave her Guardian, Gorgyra was not able to forgive herself and requested to become a Cie'th as punishment. The last Guardian, Caius Ballad, was freed from his l'Cie fate by Etro who placed her own heart within him, granting him eternity to protect Yeul's reincarnations until the end of time. Caius came to replace the Oracle Drive in that he would remember all of her visions of time and space.
When Yeul predicted the fall of Paddra 170 years before the War of Transgression, it caused a great disturbance in the city and Paddra fell due to the civil war that broke out among its people. Shortly before the fall of the city, the remaining Farseers abandoned the city and went into the wild, avoiding the rest of mankind, becoming a nomadic tribe.
A nomadic people encountered in the Archylte Steppe in an unknown year may be descendants of the Farseers, although this is never specified, as neither Yeul nor her Guardian Caius are met among them. Seven hundred years after the Day of Ragnarok, the Farseers settle in a place called the Dying World and are the last remaining humans on the planet, but even this last settlement dies out, until only one member of the tribe is left: Noel Kreiss. Noel sets out on a quest to travel through time in order to change the future of the world and stop it from falling into ruin.
According to Daisuke Watanabe, lead scenario writer for Final Fantasy XIII-2, the Farseers still exist in the present days of Final Fantasy XIII-2, and even in the time period Noel comes from. They live hidden, far away from all other human beings. They are aware of the prophecy that warns of potential conflicts between humans; they therefore avoid contact with modern civilization and chose never again to use technology like the Oracle Drives.
The Farseers have the eponymous theme called "Song of the Farseers". It features a brooding melody and has Joelle providing a lyrical overture composed of a simple phonetic sound. Its melody is based off the track "Paradox" and is identical to "Yeul's Theme" with the only exception being the lack of literary lyrics.
"Farseer" derives from two English words: "far", which describes a long distance, and "seer", a person who looks into the future.