Two men have been called "the last ninja." The first is Fujita Seiko, who lived over a hundred years ago. Introducing himself as the last ninja, he held demonstrations throughout Japan and researched ninja arts. Going over footage of Fujita, we discuss the principles he taught. The second is Kawakami Jinichi, who is still alive today. We introduce the training he's continued for over sixty years and scientifically analyze a ninja breathing technique called "okinaga" to determine its effect.