i think when he becomes the host of all the tailed beasts.. Basically the vessel for all of them, inside of him, maybe that'll make them combine since they'd all be in his body and he'd control the juubi, but what i don't get is, if he's going to beat Edo Madara, How will Sasuke ever stand a chance? That's just ridiculous to say that if naruto can beat edo madara, the top uchiha, that Sasuke could stand a chance. That's the real question.