Ninja are the covert and mercenary agents in Japan. They are famously known for both conducting espionage and assassinations and for wielding "magical" abilities. In the Gintama universe, the ninja play notable roles in the story and in fact some of the recurring characters are trained ninja.
History[]
Little is known about the ninja's origins but there are scarce records of commoners and even sometimes samurai themselves, being hired and trained for infiltration, murders and guerrilla warfare. But it was constantly referenced that these tasks were not honorable for normal samurai. It wasn't until the 15th century, during Japan's civil war period, when villages specifically trained in the ninja arts, the Iga and Koga provinces, were formed. Many feudal warlords hired them to spy or kill their enemies and it is in this civil war period that they rose to the height of their power and influence.
Their power waned when Japan was unified by the future Tokugawa shogunate.
Oniwabanshuu[]
The Oniwabanshuu were a small group of Iga ninja tasked with being the shogun's special forces, created during the early Tokugawa shogunate. Their duties include protecting the shogun and his family, information gathering, and assassinations. They had replaced the Tenshouin Naraku as the Shogun's go to during this period.
During Sada Sada's reign, a renegade Oniwaban named Jiraia tried to assassinate him and failed. But due to this, the ninja were dismissed and the Naraku reinstated. They were still occasionally hired by other officials and organizations for their services. Their leader was Hattori Zenzou's father then Zenzou himself after his father retired due to injuries sustained by Jiraia. The father later dies of old age while Jiraia was killed by his student, Tsukuyo, with the help of Gintoki.
Shimatsuya are assassins for hire, with Sarutobi Ayame being recognized as the foremost lethal assassin among them.
Internally, there is an independent unit that goes after rogue assassins who are deemed by the higher-ups to have turned traitors or have become a liability: Annihilation Punishers
Hyakka, the self-defense guards in charge of protecting Yoshiwara from outside trouble-makers, as well as preventing Yoshiwara 'inhabitants' from escaping.
Kyuubi Kitsunebi, The Ring Kyuubi were a professional organization which originated and formed spies that would learn to master the art of thievery and then be sent into enemy countries that were at war on the moment bringing chaos through darkness into the battlefield. One broke away to become a chivalrous bandit, robbing the rich to give to the poor.
