Theory #1
I believe that Madara is going to steal Sasuke's EMS and obtain a more powerful Sharingan. In Chapter 661, after he defeated Tobirama, he says he's nurturing a new eye, but he doesn't know if it'll stick with him. I think he's referring to his other rinnegan he still is missing. He plans on regaining it, but soon after, or even before, steal Sasuke's EMS. Right after he says this, the first panel on the next page is a picture of Sasuke's EMS. That picture might be hinting at this...
Theory #2
I believe that Spiral Zetsu has the ability to take over bodies that he's attached to, and amplify their power greatly. We know that he merged with Obito and used devastating wood release jutsus against the Bloody Mist shinobi. Obito, at this point, had shown no wood release whatsoever. In Chapter 661 Madara asks White Zetsu how a fight is going over "there"? White Zetsu says it's under control, and the "insides are surprisingly good". In 662, I think we see the fight they were discussing. Spiral Zetsu is fighting the Third Hokage, and more of the alliance. He is using Sage Hashirama-Level wood release. I believe Yamato, a much more skilled wood release user than Obito was, is currently inside white Zetsu ("the insides are surprisingly good"), which would explain why Spiral Zetsu can use these powerful jutsus. Orochimaru also notices something odd about Spiral Zetsu. He might be able to sense that it is Yamato...
I believe that Madara is going to steal Sasuke's EMS and obtain a more powerful Sharingan. In Chapter 661, after he defeated Tobirama, he says he's nurturing a new eye, but he doesn't know if it'll stick with him. I think he's referring to his other rinnegan he still is missing. He plans on regaining it, but soon after, or even before, steal Sasuke's EMS. Right after he says this, the first panel on the next page is a picture of Sasuke's EMS. That picture might be hinting at this...
Theory #2
I believe that Spiral Zetsu has the ability to take over bodies that he's attached to, and amplify their power greatly. We know that he merged with Obito and used devastating wood release jutsus against the Bloody Mist shinobi. Obito, at this point, had shown no wood release whatsoever. In Chapter 661 Madara asks White Zetsu how a fight is going over "there"? White Zetsu says it's under control, and the "insides are surprisingly good". In 662, I think we see the fight they were discussing. Spiral Zetsu is fighting the Third Hokage, and more of the alliance. He is using Sage Hashirama-Level wood release. I believe Yamato, a much more skilled wood release user than Obito was, is currently inside white Zetsu ("the insides are surprisingly good"), which would explain why Spiral Zetsu can use these powerful jutsus. Orochimaru also notices something odd about Spiral Zetsu. He might be able to sense that it is Yamato...
