A ninja was a mercenary or a covert agent in feudal Japan. The functions of a ninja included surprise attacks, espionage and deception. Their covert methods of waging irregular warfare were deemed despicable and beneath the honor of the samurai. Though ninjas as specially trained spies and mercenaries, appeared in the 15th century during the Sengoku period i.e., between 15th–17th centuries, their antecessors may have existed as early as the 12th century. In the unrest of the Sengoku period, mercenaries and spies became active for hiring in Iga Province and the adjacent area around the village of Koga. It is from the clans of that area from where much of the knowledge of the ninja is drawn. The ninja faded into obscurity following the unification of Japan under the Tokugawa shogunate in the 17th century, A number of ninja manuals that are often based on Chinese military philosophy were written in the 17th and 18th centuries, most observably the Bansenshukai (1676). Ninja had become a topic of popular imagination and mystery in Japan by the time of the Meiji Restoration (1868). Ninjas were presented prominently in legend and folklore where they were associated with legendary abilities such as ability to walk on water, invisibility and control over the natural elements. Consequently, their perception in popular culture is based more on such legend and folklore rather than on the spies of the Sengoku period.
In this sub category you can download free PNG images: Ninja Animals. In this category "Ninja" we have 12 free PNG images with transparent background.