The Oniwabanshuu
Ok, I think this is how it goes. The Oniwabanshuu was a group of ninja spies (thats where Misao got here instinct ^_^x). When they saw the "Black Ships" arrive in Japan, Okaashira ( I think thats his name, hes Misao's Grandfather) told Okina to start a defensive force in Kyoto where Okaashira thought the "Black Ships" might strike.
                                             --1854
After a while, Aoshi was hired by Kanryuu to bring Megumi back to him,but once Megumi went to Kenshin and Sanosuke for help, they defeated the Oniwabanshuu. Once Aoshi relized that he wasn't doing what the Oniwabanshuu needed to, he told Kanryuu that he wouldn't take it anymore. AND THEN KANRYUU CALLS HIS EVIL MONKEY ARMY ON THE ONIWABANSHUU!!!! J/K, he brings a revolver out and kills the Oniwabanshuu (old), them getting in the way to save Aoshi's life.
Warning! Spoilers Ahead!
Okina - Ensatsu Goukoukon
Aoshi - Kodachi Nitouryuu
Misao - Kansatsu Tobi Kunai
Hannya - Shinwanjutsu and Kenpo and Kagitsume
Beshimi - Rasenbyou
Hyottoko - Kaentoiki ( Fire Breath )
Kuro - Kotewa Shuriken
Shiro - Kotewa Shuriken
Omasu - Enkei Shuriken
Okon - Kunoji Shuriken
"We could. And could it not happen now? In this Tokyo? However, to do so now would have no meaning. What has meaning is the true strongest of the Bakumatsu. That is the Oniwabanshuu. This is proof."
                          + Shinomori Aoshi +
In ancient Japanese, 'Banshuu' in 'Oniwabanshuu' means a ninja who protects the Edo Castle.
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