Ninja culture originated in Japan during the feudal era, particularly in the 15th and 16th centuries. Ninjas, or shinobi, were covert agents skilled in espionage, sabotage, and guerrilla warfare. They often worked for samurai or feudal lords, using their stealth and agility to gather intelligence or carry out missions without being detected. The training of ninjas included martial arts, survival skills, and the use of various weapons, such as shuriken and katana. They also practiced techniques for disguise and deception. Today, ninja culture is popular in media, influencing movies, video games, and literature, often romanticizing their mysterious and skilled nature.