
Originally Posted by
Thunder
Can't find the chapter but apparently it's in the "itachi pursuit arc" and I got this from narutopedia:
"After Orochimaru's defeat at the hands of Sasuke, Kabuto integrates remains from Orochimaru's body into his own. The remains start taking control of his body, and Kabuto is in a constant struggle to keep them from spreading. ..."
There was something in the manga that lead me to believe he's literally being taken over by orochimaru and foreshadowed his return(because come on, oro's more badass than kabuto). But idk.