Originally an army of volunteers founded by Takasugi Shinsuke during the last years of the Joui War, the Kiheitai used to consist of young men who wanted to participate in the war. One of these soldiers was Hiraga Saburou, the son of Hiraga Gengai. After the samurai had lost the war, numerous Kiheitai members, including Saburou, were executed in a post-war purge by the Bakufu. As a result, the group went underground and became more Jouishishi-extreme. Since then, it focused on overthrowing the Bakufu by any methods possible and became wanted criminals.
Shinsengumi Crisis Arc
Patriot Reunion Party Arc
To kill Takasugi's former comrades, the Kiheitai, mainly Takechi Henpeita and Kijima Matako, set up a trap under the guise of a "Patriot Reunion Party." Assuming the name of Kurokono Tasuke, a presumably deceased Joui participant, they invited Katsura Kotarou, Sakata Gintoki and Sakamoto Tatsuma to the party, where they used sleep-inducing gas to capture Katsura and Sakamoto.
As a horrified Gintoki kept himself in the tatami room, Takechi and other members, disguising as basketball players, cornered and attacked him with gas. However, they were defeated by Gintoki, and Matako was forced to release the other two samurai by the real Kurokono.
Returning to Earth, Kiheitai arrived in time to help Earth from Utsuro and the invading Amantos who wants to destroy Earth.