Claire Farron’s father died when she was very young, and her mother passed from illness when she was 15. Left an orphan, Claire raised her younger sister Serah by herself, and took the name “Lightning” both to cope with the loss of her parents and to become more like an adult. This quickly led her to become somewhat cold and distant from everyone except Serah.
After she graduated high school, Lightning joined the Bodhum security regiment Guard Corps, where she rose to the rank of Sergeant. However, this led to her spending less and less time with Serah, who eventually became a l'Cie, putting herself in great danger. Lightning quit the Guard Corps to save Serah, but she eventually ended up becoming a l'Cie herself in order to free Serah from her crystalized prison.
Lightning is revived after 500 years by the god Bhunivelze. The world is set to end in thirteen days, and Lightning is chosen as the Savior, a spiritual guide for humanity, which has ceased to age due to the influence of chaos. In return for Lightning's help, Serah will be resurrected. Aided by Hope, Lightning frees her former allies of their emotional burdens, reunites with Odin in the form of a white Chocobo, and frequently crosses paths with Lumina, the physical manifestation of Lightning's suppressed vulnerabilities. Lightning begins to doubt her humanity, and, when she learns that Bhunivelze stole Serah's soul and manipulated Lightning's memories, she plans to betray him after he has finished building the new world. When the end of the world arrives, Lightning fights Bhunivelze, who wants to transform humanity into his ideal image and has been shaping Lightning to become Etro's replacement. Although she is prepared to fulfill her new role and abandon her human life, Lightning instead chooses to call for help and accept Lumina as a part of herself. Everyone she has saved, including Serah, unites with her and defeats Bhunivelze. Lightning then witnesses the creation of a new universe, into which she goes with her allies and the souls of humanity. In the epilogue, she is seen traveling to reunite with one of her friends.