I think orochimaru will be the final villain in the series.
It seems that all his research seems to be pointing to him acheiving the power of the Sage of the Sixth Paths which judging by recent chapter the only thing he needs is Sasuke.
Currently orochimaru has:
Knowledge and ability to use sage mode from Kabuto
Absorved Zetsu to acheive senju DNA
Knows more about the sage than any one in the show
Can't die so he has unlimited Chakra
The only thing he needs is an EMS which is what he wants from Sasuke.
It seems that all his research seems to be pointing to him acheiving the power of the Sage of the Sixth Paths which judging by recent chapter the only thing he needs is Sasuke.
Currently orochimaru has:
Knowledge and ability to use sage mode from Kabuto
Absorved Zetsu to acheive senju DNA
Knows more about the sage than any one in the show
Can't die so he has unlimited Chakra
The only thing he needs is an EMS which is what he wants from Sasuke.