Do you think that Tsunade and Kabuto are the "real immortals" (by this, I mean not dying of old age or any degenerative diseases) given the fact that they have mastered Kabuto's technique of cell creation? Recall: 1. Tsunade's Genesis Rebirth hastens cell division. The technique costs the user some extra years...refer to the soliloquy of Shizune (the Great Sannin Battle). 2. Tsunade said that Kabuto's Tummy Regeneration technique enables the user to create new cells. 3. She used this to cure Lee. Now: Aging is a progression of irreversible change that eventually leads to death. It occurs at the level of individual cells, tissues and entire organs. Meaning, if one can constantly create new cells, not just regenerate them through catalyzing cell division, then one is immortal. Moreover, Tsunade possesses a greater advantage than Kabuto coz she can now negate the effects of Ninpo Sozo Saise. She can use it anytime without worrying of shortening her lifespan. What do you reckon?