The Blue Beast vs. Six Paths Madara

is episode 418 of the Naruto: Shippūden anime.

Summary
As Orochimaru and his team reach Sasuke, they realise that the unknown chakra signature is that of Kabuto. Since Kabuto has assimilated other people into himself, his chakra signature has become unknown, explaining why Karin could not identify the person near to Sasuke. Kabuto explains that he has decided to save Sasuke, after coming to realise who he was, thanks to the Izanami. Elsewhere, Guy releases the Gate of Shock, which fails to damage Madara. Knowing that the Seventh Gate failed, Guy realises he must use the Gate of Death, which he knows will kill him. He remembers his time with his father, where he failed to graduate and decided to run 500 laps in order to enter the Academy as an alternate student.