Tobi uses Kamui to phase through attacks. He does so using Kamui. You can see this based on the fact that in the latest chapter he phased though Naruto's rasengan only to have his arm blown off because Kakashi sent it to the alternate dimension. The exact same place where Tobi phased through. This leads me to believe that Tobi is definitely Obito or related to Obito, and that Sauske and Itatchi are directly related to Madara. I think that Ms techs stay the same through blood and different families gain different abilities. Which is why Tobi cannot use susanno. Your thoughts.:shrug: