Human Weapon - Ninjitsu

In the ultimate search for a HUMAN WEAPON, mixed martial artist Jason Chambers and football pro Bill Duff put their bodies on the line as they train in the most lethal forms of combat before going toe-to-toe with masters of each fighting style.

They travel back to Japan to learn Ninjutsu. They learn different weapons that the ninja used, as well as tactics & warfare.

They are studying under Masaaki Hatsumi.

According to Wikipedia.

Masaaki Hatsumi is the 34th ninjutsu Soke, or Grandmaster, and founder of the Bujinkan Organization, currently residing and teaching in the city of Noda, Chiba, Japan.[3] He is also a doctor of orthopedics, specializing in the mending of bones.

Beginning in childhood, Masaaki Hatsumi studied several popular martial arts. After teaching martial arts to the U.S. soldiers stationed in Japan he noticed that the larger and stronger Americans had an advantage in bouts when using the same techniques. [5]He began to question the legitimacy of modern martial arts training and started to search for an art where persons of equal skill truly were equals, even if the other one was more muscular. It was after this time, while studying the ancient Japanese weaponry of the Masaki Ryu under Yumio Nawa, that he learned of ninjutsu and a martial artist named Toshitsugu Takamatsu who was proficient in this art. In 1957 he and Fukumoto Yoshio began making regular trips to train with his new teacher (who resided at the time in Kashiwabara, in Nara), taking a 15-hour train ride from his hometown of Noda in Chiba. This training continued for 15 years until the passing of Toshitsugu Takamatsu in 1972.

It must be awesome to learn to be a ninja, but it's pretty deadly by the looks of it. Every maneuver results in a killing blow.