Re: Kabuto's 6th Casket, The Elder Brother, and Tobi's Identity
if shisui is itachi's senior. there's this possibilty that he is in his teens during the 4th's time.
shisui could have found madara's corpse and stuck it into his own eye socket, thus giving him unique sharingan powers even without gaining MS or EMS.
it was also mentioned that the tech used on the bloody mist kage was the same with the one used by danzo.
the only problems then would be how danzo gained shisui's parts and why did the tobi that fought 4th hokage already have gooey limbs.
if we find how this happened, then there could be a chance tobi=shisui. it's farfetched but there's still a possibilty.