Jacob Ross at Save/Continue writes:
"Lightning and Hope suffered great personal loss, and eventually sought revenge as a way to deal with the grief. Snow and Vanille were responsible for the suffering of others, and buried their guilt under protective personas. Sazh slowly lost hope that Dajh could ever be saved, and eventually planned to sacrifice his own life just to see his son one more time. Though the rejection of an unwanted fate may be Final Fantasy XIII’s most prominent theme, it’s these redemptive journeys from tragedy to reconciliation that are its most poignant."