Ninjas were covert agents in feudal Japan known for their skills in espionage, sabotage, and guerrilla warfare. They often operated in secrecy, using stealth and deception to achieve their objectives. Unlike the samurai, who followed a strict code of honor, ninjas were more flexible in their methods, allowing them to adapt to various situations. The term "ninja" is derived from the characters for "to endure" and "to hide." Ninjas were trained in various martial arts and were proficient in using weapons like shurikens and katanas. Their legacy continues to influence popular culture, appearing in movies, video games, and literature.