SHINOBI

A shinobi was a feudal-era spy in Japan who was trained in the Japanese art of ninjutsu (roughly "the art of silent movement"). Ninjas, like samurai, obeyed their own distinctive rules, called ninpo. According to some observers of ninjutsu, the skill of a ninja is not assassination but infiltration. Ninja comes from the Japanese language which reads nin which means to infiltrate. So, the special skill of a ninja is to infiltrate with or without sound.