The movie more or less speaks out against conformity and encourages individual thought, as the main character leaves the only home he ever knew in an effort do to the right thing. He also risks his life to bring down an organization with evil intentions. But the fact that he meets violence with violence is a much iffier message. And there's a bit of confusion surrounding the organization -- although there are nine clans, Raizo is only concerned with taking down one of them.
Wall-to-wall extreme martial arts violence, with gallons and gallons of blood spewing, splatting, splashing, spraying, and gurgling everywhere. But it's all comic book-style fantasy battle violence. Several characters lose limbs or heads, some of which go flying a good distance from their original locations. A female ninja-in-training gets her face sliced. A man's head is repeatedly battered into the urinals in a public restroom. A throwing star is extracted from a gaping stomach wound. Most disturbingly, a ninja master whips the feet of a young boy, a ninja-in-training, creating painful-looking gashes on the boy's soles.
A teen couple -- both ninjas in training -- shares a tender kiss. In another scene, they rest their heads on each other's chests, listening to each other's heartbeats (while clothed and in the open).
Significant stretches of the movie are profanity-free, but "f--k" is used several times overall. Other words include "s--t," "dumbass," "damn," "Oh God" (used as an exclamation), and "scheisse" (the German word for "s--t").
In one scene characters drink Pepsi and prominently display Pepsi bottles, but the name is never mentioned aloud.