Did you know this about Ninja?
Like in the movie, the Iga Ninja had to be heartless as Raizo (Rain) and the other Ninjas had to be, because in early times the Iga Ninja would often be hired by two different leaders and would end up having to kill their own kind. Secondly, they actually did have a code called Nukenin Seibai (which is different then the term in the movie however…) this translates to “deserters shall be punished”. A theme very much seen in the movie.
The other basis for the Ozunu in the movie is the Fuma Clan (Ruffian Clan), the Fuma clan were known for their overall brutality and total disdain for their own and others lives… They were very intense, as is the clan in the movie… They could not be reasoned with as they had no care for others lives and were paid heavily for assassinations and use as body guards.
Talking about servants, warriors and the war techniques, it would be unfair to mention the samurai. The Samurai, when translated means to serve thus in a real sense it is either serving his lord or master or serving one’s own country. For one to become an effective server of the lord and nation one should be educated with fighting tactics and that includes expertise in martial arts.