Ninjas were Japanese warriors who were trained in the art of assassination and espionage. They would usually be given special missions do to this skill.
Ninjas lived in the 15th century. They mostly resided in Japan.
They would work under their feudal leaders, called Daimyo or Shogun. Sometimes, ninjas were also in a ninja organization.
Ninjas used a variety of weapons, from knives to swords, to martial arts. For a more detailed explanation on weapons, see Ninja Weapons above.