Trying to sort out the backstory so far.
Major Characters:
Ryuko Matoi
Isshin Matoi
Satsuki Kiryuin
Mr. Kiryuin
Mrs. Kiryuin
Aikuro Mikisugi
Tsumugu Kinigase
Kinue
Factions:
Life Fiber Research Team
Nudist Beach
Honnouji Academy
Weapons:
Goku Uniforms
Junketsu
Senketsu
Scissor Blade
Originally, the Life Fiber Research Team consisted of Aikuro, Tsumugo, Isshin, maybe some others and probably headed by Kinue. Working under the sponsorship of the Kiryuin family, they looked for ways to create super powered uniforms that would enable wearers to far exceed the limits of the human body. Somewhere along the way, Kinue was consumed by a prototype Kamui, probably Junketsu, and realizing the horrific possibilities of Life Fiber clothing, Aikuro, Tsumugo and Isshin left the research team. Junketsu was sealed away until one day when Satsuki could wear it (why? I have no idea).
With the results of the research, the Kiryuin family began mass producing Goku uniforms, using them to overwhelm the rest of Japan's high schools and create a totalitarian society based around Honnouji Academy, with Kansai as the last stronghold against the Kiryuin family's rule. Seeing this abuse of their research and Kinue's legacy, Aikuro, Tsumugo and Isshin formed Nudist Beach, a resistance against the rule of the Kiryuins. Using their experience with the Life Fiber research, they developed anti-uniform weaponry like Tsumugu's needles, the ultimate result of which is the Scissor Blade, a weapon not only capable of destroying Goku uniforms, but also taking away their Life Fibers.
Realizing that even with the Scissor Blade, the Nudists were limited by their human bodies while the Kiryuin still retain possession of Junketsu, Isshin recreated the Kamui using his past research as a last resort for the Nudists, which is Senketsu. Getting wind of this new Kamui, the Kiryuins (maybe Satsuki herself) attempted to steal it, but they could not find it. Instead, they managed to acquire the Blue Scissor Blade before they were forced to retreat.
Now, Ryuko, inheriting the will of her father, shows up at Honnouji Academy to challenge Satsuki. Satsuki, for her part, knows far more about the history of the Kamui than Ryuko, Aikuro and maybe even her parents realize. I think her plan is to let Ryuko acquire all the Life Fibers from the club heads, and then take it all in one go by defeating Ryuko and Senketsu while using the Blue Scissor Blade.
