Junketsu

Junketsu (純潔 lit. purity) is a Kamui made by the Kiriyūin family. It was sealed away by Ragyō Kiryūin because of its uncontrollable power. It is eventually donned by Satsuki Kiryūin in order to combat Ryūko Matoi and her own Kamui, Senketsu. During Satsuki's battle with Ragyō, Ragyō succeeds in stripping Satsuki of Junketsu and dons it herself. Later, Ragyō and Nui Harime both help Junketsu "wear" Ryūko, and completely synchronizes with her, becoming one with the Life Fibers. However, Ryūko breaks free of Junketsu's control at the end of Episode 21. It is later recovered by and worn again by Satsuki in Episode 22, albeit "retailored" with the sisters' blood and some of Senketsu's Life Fibers.