possible people inside the box that would shake up Madara:
1) Hashirama- unlikely though, as Hiruzen evidently kicked his rear when they fought, making him less of a threat compared to other potentials.
2)Hiruzen- one of the strongest ninja ever, but Madara hasn't really had a lot to do with him so I doubt it'll be him in there
3)Orochimaru- possible, although I think even Kishimoto is getting sick with him coming back from the dead
4)Madara's brother- one of the more likely theories, as it would imply that Kabuto knows more of Madara's history than others know. I think as far as we can tell, the only ones who definately know about his past are Sasuke and Zetsu. Possibly Kabuto in this case.
5)Minato- Madara would know the capability of the fourth hokage and fear him after witnessing Minato defeat the 9-tails.
6) the Sage of 6 paths- definitely cause for concern in Madara's case, but if Kabuto had that sort of power available, surely he could take Sasuke by force?
1) Hashirama- unlikely though, as Hiruzen evidently kicked his rear when they fought, making him less of a threat compared to other potentials.
2)Hiruzen- one of the strongest ninja ever, but Madara hasn't really had a lot to do with him so I doubt it'll be him in there
3)Orochimaru- possible, although I think even Kishimoto is getting sick with him coming back from the dead
4)Madara's brother- one of the more likely theories, as it would imply that Kabuto knows more of Madara's history than others know. I think as far as we can tell, the only ones who definately know about his past are Sasuke and Zetsu. Possibly Kabuto in this case.
5)Minato- Madara would know the capability of the fourth hokage and fear him after witnessing Minato defeat the 9-tails.
6) the Sage of 6 paths- definitely cause for concern in Madara's case, but if Kabuto had that sort of power available, surely he could take Sasuke by force?