In the Infinite Tsykuyomi, Kabuto Yakushi had finally found his place and his identity. He was as Mother Nono - who had lived on - christened him, and his brother was beside him as all three of them ran the orphanage, caring for those on the outside who sought their aid, and the young ones who had no place outside these walls would either call this place their real home or would find a new one. Nothing mattered but this content, and no one would come and ruin it for him again.
Orochimaru and Team Taka sometimes stopped by, but he didn't mind at all. He found that he liked having friends in them - including Sasuke Uchiha who also returned home to the Leaf, to where he belonged, too. His friends and comrades forgave him for the deeds he committed as he, too, had been lost.
In the real world, Kabuto was entombed with his former master and Team Taka, smiling and at peace for the first time in his life - and it would be the last. He would be the same as they would be. The first things to go were his trousers, leaving his scaly white body naked. If anyone saw him, they'd be utterly disgusted. At the sight of him along with the sleeping snake that grew from the middle of his body, ever since he absorbed Orochimaru's blood and jutsu.
Kaguya-hime's voice spoke to him, talking to him in nearly the same way Nono used to speak to him, promising him that he had no need to be scared of where he belonged or who he was. He was her soldier, and he had nothing to fear - he would not fear her as he once feared the Snake Sannin.
It took a year to a few more for him to change completely. His Sage Jutsu was completely gone and so were the rest of his and Orochimaru's chakra. His brain drained and shriveled along with the rest of him. His lean muscles became fragile like paper, his glasses fell from his nose - the ones he inherited from the one he called Mother - and vanished into dust, and the snake thinned until it became like a dead tree branch. He looked, as a whole, like a real snakeskin left behind as its owner abandoned the shell for a new, fresh look. And that was what came his way.
That voice continued to speak to him as she did to the others she reprogrammed into her obedient soldiers. Telling him to forget that he was Kabuto, that it was never his name to begin with - which was true, admittedly - and that he was to be named the same way as the others: White Zetsu.
The cocoon tightened around him as his body regained its mass, though features changed if his revitalized flesh remained white and losing the scales while becoming more cracked. The snake suctioned back into his body, vanishing as if it had never been. His gray hair shortened and turned green, his yellowish eyes gaining a light green shade, and he looked a tad more humanistic than before.
Kabuto Yakushi was no more, just White Zetsu. He was released from the tree along with the ones who used to be his feared mentor and the ones they experimented on together. But as his princess promised him, there was nothing more to worry about except the three invaders on the way.