We should known already that Kishi is a DBZ fan and i believe he will use the scense where Goku spirit assisted Gohan to defeat Cell in DBZ .
From rereading the manga ,i believe Itachi did something special to Sasuke before he departed from the world of the living.I am sure Itachi was aware that Madara was alive because he had some sensor skill (he was able to detect kabuto exact location).One of the possibilities is itachi casting another genjutsu while showing Sasuke flash back.The other jutsu will activated when Sasuke need really in serious danger/near death.When the genjutsu activated,then Itachi will spawn giving Sasuke the legendary weapons (yata mirror and totsuka blade).This will assist him to defeat Madara .
The picture above is similar to when itachi transfer his sharingan powers to Sasuke before he die the first time.Notice there is chakra around both Sasuke and itachi,which could be some chakra/spirtual transfer of the legendary item(spiritual weapons)
You must be registered for see images
From rereading the manga ,i believe Itachi did something special to Sasuke before he departed from the world of the living.I am sure Itachi was aware that Madara was alive because he had some sensor skill (he was able to detect kabuto exact location).One of the possibilities is itachi casting another genjutsu while showing Sasuke flash back.The other jutsu will activated when Sasuke need really in serious danger/near death.When the genjutsu activated,then Itachi will spawn giving Sasuke the legendary weapons (yata mirror and totsuka blade).This will assist him to defeat Madara .
You must be registered for see images
The picture above is similar to when itachi transfer his sharingan powers to Sasuke before he die the first time.Notice there is chakra around both Sasuke and itachi,which could be some chakra/spirtual transfer of the legendary item(spiritual weapons)