Violence and nudity in anime seems to be a common thread in most of the popular titles. Why is that? Why does anime have to have such graphic detail of violence? I remember watching such films as Fist of the North Star and Akira and thinking that this would never be shown on T.V. or in movie theatres because of the violence. This is not to say that I dislike it. It's just that some anime seem to have violent or nude scenes that need not be in.
The real heart of the problem is that anime often deals with adult issues that often require some of these extra scenes to emphasize the point. For instance in Jubei, there are ample scenes where people are killed and the full death scene is shown, like when Jubei confronts Tessai. There are bodies and body parts everywhere. It is necessary to show this because it moves the story forward and allows the viewer to not only experience the pain and grief of the moment, but also to emphasize the fact that these are dangerous times and anything can happen. The violence is also needed because the plot deals often with the supernatural powers that are at work. It is hard to judge how much the heroes are the underdogs without seeing some of the devastation and the ease at which it is being done.
This is not to say that all the violent scenes are necessary. There are some anime that have many scenes that need not be shown. I will not mention any examples because some are often tasteless. In the end, it is often how real the scenes are that either make them repulsive or enjoyable to people.