It had started off slow. The line where his human flesh ended and the artificial parts that Madara had attached to him in order to save his life had begun to blur. Then, the line between started to creep millimeter by millimeter as his human flesh gave ground.
He'd tried to stop it at one point when he'd finally noticed that his human skin was increasingly becoming a veneer. He'd failed.
There was a time he'd cursed his fate. That had stopped long ago however. That had stopped the day his heart had gone cold and stopped beating altogether.
Some days he wonders if he were ever human. It's easy to forget sometimes.