Ninjas
The ancient art of Ninjitsu began over 800 years ago when a faction of the Samurai would would not serve the higher class. The ninjas went to Iga and Koga, desolate mountain regions. While at Iga and Koga, they devoted their time to mastering every martial arts form in existance. They would be hired as assasins and spies, and as time passed, they begame integrated in Japan's government. Ninjas became secret service agents and special service agents. Now even the Samurai feared the Ninjas, and they have been enemies since.
Ninjas and ninja practices work to prevent further danger and promote protection. Along with the ability to perform seemingly inhuman things, being a ninja will elevate and enlighten the spirit. Not only do they need physical training, but much discipline, or it could lead to failure. Ninjitsu is meant to provide security, not outrageous fight scenes wtih an archenemy. Once a ninja accheives mastery, there is no such thing as a surprise.