Kurama is starting to feel naruto like a friend... Or maybe not...??? I remember kurama saying : "You will pay for that!!! NARUTOOO!!!!" When naruto defeat him and mastered KM... Maybe hes acting like that until he finds an oportunity to take over narutos control and go wild... If you see that chapter again you'll see that kurama is too confident when hes talking about taking revenge and he seems to had a huge hatred inside him while he slowly fades back to the darkness of his cage... What do you guys think...?