Facts:
- Ninjas are mammals.
- Ninjas fight ALL the time.
- The purpose of the ninja is to flip out and kill people.
Ninja were Japanese people trained in assassination, espionage, and a variety of martial arts. They have developed a prominent place in Japanese and American popular culture, and are generally agreed to be seriously cool. To quote the website Real Ultimate Power, "These guys are cool; and by cool, I mean totally sweet."
For some time on the Internet, the idea of pirates being the natural rivals of ninjas has circulated.