Ninja, originally known as the Shinobi, has been considered the most popular, the most mysterious, the most unorthodox, and the most deadly form of combat and espionage in the world. Emerging as mercenaries around the 15th century, it was a warrior clan of spies, raiders, arsonists, and assassins.

For the most part, Ninja training was kept hidden from the public eye and only a select few learned this very secretive artform. However, everything changed in the 1990s as Ninja was brought into the limelight by Stephen Hayes. He was not only the first American to be accepted as a student in the art of the Ninja in Japan but was the first individual to pioneer Ninja in the United States.