Isshin Matoi

Isshin Matoi (纏 一身) is the father of Ryūko Matoi and Satsuki Kiryūin and the man who created Senketsu and the Scissor Blade. He was a scientist who researched Life Fibers, and the founder of Nudist Beach. He was murdered by Nui Harime.

His goal, as stated by Aikurō Mikisugi, was to "thwart the ambitions of the Kiryūins by using the Kamui".

It is revealed in episode 19 that Isshin was in fact Sōichirō Kiryūin who faked his death and disguised himself so he could raise Ryūko.

Appearance
Isshin Matoi is a very old man. He has a thin frame, a hunched back, white hair and a very long beard. His clothes are ragged and he uses an eyepatch in his right eye.

It is possible that he made Senketsu in his image, since his eyepatch and mustache greatly resemble Senketsu's features.

History
Isshin was a scientist who worked alongside Tsumugu Kinagase, Kinue Kinagase and Aikurō Mikisugi in his research of Life Fibers. He worked under orders from the Kiryūin family, and once he learned of the potential threat posed by the Life Fibers, he created the secret organization Nudist Beach, as well as Senketsu and the Rending Scissors, to counter them. In the 19th episode, we discover that he is Sōichirō Kiryūin, the real father of Ryūko Matoi(and Satsuki Kiryūin), and that he changed his appearance to escape from Ragyō Kiryūin, his wife, with the younger daughter.

Six months before the events of the main story, Isshin was attacked by Nui Harime, who was sent to his laboratory to retrieve some important creation under Satsuki Kiryūin's orders. Knowing that, he hid Senketsu and lured Nui into stealing the Rending Scissors. He fought against her using them, but was eventually overwhelmed and mortally wounded by the scissors when Nui managed to snag them from his hands. In a moment of distraction upon hearing Ryūko's voice, who went to the house following a letter from Isshin asking her to have a conversation, Nui ended up having her left eye taken by Isshin, who broke the scissors in two halves. She took the scissor half used to damage her eye and fled. Ryūko found Isshin laying on the ground with the other scissor half driven through his body. He told her that, if she wanted to have a peaceful life, she was to leave him there and walk away. If she wished to fight in his place, however, she should take the very Scissor Blade that was used to wound him. According to him, she would be sure to find Isshin's assailant, but a cruel fate would be in store for her.

Before he could say anything else, Ryūko saw Nui wielding the Scissor Blade, but couldn't make out the silhouette. With the other half of the scissor in her hands, she immediately gave chase, ignoring the pleas of her father, who said he still had much to say. The mansion then exploded, Isshin still inside.

At some point before his death, Isshin sent a letter to Aikurō asking him to lead Ryūko to Senketsu.

Relationships
Ryūko Matoi

"According to Ryūko herself, they never had a close relationship and were constantly at odds with each other. Isshin spent a great part of his time with his research, leaving him little time to spend with his daughter, which, added to the lack of a mother, led her to lead a lonely life and become a juvenile delinquent. However, he obviously cared for her, as seen when he sent a letter to Aikurō requesting him to aid her."

Satsuki Kiryūin

Although Satsuki never knew it, Isshin Matoi was her father who disguised himself in order to raise Ryūko.

Memorable quotes

 * "If you take that Scissor, you're sure to find the person who killed me. But a cruel fate will lie in store for you..."
 * - Isshin's final warning to Ryūko.