Ninjas are shady characters full of secrets, and their history is likewise shrouded in mystery to keep outsiders from learning of their ways and ruining all their ninja fun.
But the ninjas we see in pop culture are mutant animals, blonde Americans, and a funny fat guy in Beverly Hills, a far cry from the real shadowy assassins of yore.
The ninja's significance in Japanese history has been overshadowed by the samurai, but if they weren't as important as samurai why did Japanese Lords Hideyoshi Toyotomi and Oda Nobunaga try to kill them all off in the late 16th century?
Ninja warriors were also involved in castle sieges, sometimes using a fun ferris wheel-esque device called a Yagura to quickly launch over the wall and "jump into the fortified position".
But when they preferred a silent but deadly approach ninjas used hooked spears to slip into a castle in the dead of night, as they did in 1562 when Tokugawa Ieyasu hired a team of 80 ninjas to capture Castle Kaminojo and rescue Tokugawa's family.