So i was reading the the current manga discussion and something brought me to Tobirama Senju's Naruto wiki page. (curiosity, mostly..)
I quote:
"According to the Fourth Hokage, Tobirama was also very skilled in space-time ninjutsu.[3]"
*cough cough*
It also said
Tobirama was killed on the battlefield ..OR DID HE???
!!!!!
Time for my morning coffee. And sorry if this crackpot theory has already been mentioned in the thread. (not going to sift through 16 pages)
addition:
On a second thought, he should be sealed inside the belly of shinigami
gahh....then maybe Tobi has something related to the 2nd hokage.