biologic immortality is an inabilty to age after said creature has reached a certain point in his/her life span, either adulthood or sexual maturity. organisms with biologic immortality draw their new life-force as a by-product of either being man-eaters or by being pure of heart. there are not many characters mentioned that reveal that they have biologic immortallty or are willing to reveal that they have it.
saber she gains the youth of those she eats.
cloe through saber.
Sita she eats those that enter the buddist temple-complex she inhabits without reason.