Black Zetsu's New Body

With a few of the notable female ninjas in Konohagakure under his control, Black Zetsu next objective was to acquire a proper body for him to operation under. He knew that there was a possibility that the corrupted kunoichis could be returned to normal if his hold over them was weakened. To prevent potentially loosing all his progress, he needed to completely take over one of them so that he would still have a body to fall back to. After giving it some thought, he determined that Tsunade's body would be the most ideal. Despite her age, Tsunade's body was beautiful yet strong, and she had a lot untapped potential due to her neglecting trainings after the death of her lover. Therefore, Zestu set to undo this.

Controlling Tsunade, Zetsu had her travelled to a secluded forest and had her perform a sinister jutsu on herself. While the effect of the jutsu was slowly eroding her body, Black Zestu was channeling his own chakra into Tsunade's body, constantly regenerating back any injures before they would appear. Thus, over the next several hours, Tsunade's body was destroyed and remade hundreds of time, each time slowly becoming younger and stronger. The jutsu ate away her memories, leaving only her knowledge behind and leaving her without any personality. This allowed Zestu to take her body as the only consciousness that now resided in her body. And as her new body adapted to Black Zestu's chakra, Tsunade's power spiked even further and her appearances changed to match that of Kaguya's. Her body became taller, paler, and far more muscular and voluptuous than before.

By the end, Black Zetsu had successfully rejuvenated Tsunade's body to her early twenties. However, she was now barely recognizable. With Tsunade's own consciousness completely erased, she had become nothing but a powerful vessel for Zetsu. Even if he was to be significantly weakened, he would still continue to control her body as his own. Of course, he had to hide this little secret for now. As dawn broke, Zetsu used the same transformation technique that Tsunade often used to return her body's appearances to her old self. Satisfied, Black Zestu could now continue to build an army for Kaguya without worries.