ne never needed the eye to use the jutsu he created. Minato made a recommendation about the original ''sprinting chidori'' leaving him open.Because plot says no U_U
What I don't understand is why he can't use lightning blade as he would a Rasengan. Why did does he still need need sharingan to use it?
Look at His little Rasengan compared to Naruto,Jiraiya and Minato’s Rasengan,Thats why Kakashi created Chidori to compensated for His weak Rasengan.Why not? He has it