well actually u are all wrong xD ryuk shinigami from "death note" wins becuz he has a book that if u write the name of the person then they jus die so if i were to write ichigo he would die
I'm pretty sure that it states in the Deathnote itself that Shinigami cannot kill other Shinigami with the Deathnote. It only works on humans. And Shinigami from Naruto from what I've seen from him can only actually do damage through a mortal (that's all we ever see him do). So using this you would have to say Ichigo...since Ryuk can't do anything and we don't exactily know what Shinigami can do