The Last Ninja
 

Sounds like a follow up of a certain movie doesn't it? Jinichi Kawakami is believed to be the last ninja master. He decided not to take on a protegee because the modern world does not need ninjas. Its an interesting article explaining the mysterious origin and evolution of what a ninja became. Our very own Ninja Turtles play into the evolution of what ninjas have become. http://news.yahoo.com/63-old-enginee...053736959.html

The last ninja? In modern Japan, ninja tourist attractions do exist. They do include live demonstrations.

As for historical ninjas, they originated in medieval Japan as special forces in the armies of the era, and would later become an independent mercenary force available for hire for the various feudal warlords. They would lose their importance as the centuries went on.