Kinuhata Saiai

Saiai Kinuhata (絹旗 最愛, Kinuhata Saiai ?) is a member of ITEM, led by Mugino Shizuri. She later becomes it's leader in Volume 19, after Shizuri's defeat in Volume 15 at the hands of Shiage Hamazura.

Background
Saiai was previously a part of the 'Project of Mayday Darkness'- an experiment that used subjects who were most likely Child Errors, in an effort to replicate Accelerator's powers. It is unknown whether or not Saiai herself is a Child Error.

Personality
Despite being a powerful Psychic, Saiai is one of the most mellowed-out characters in the group, she isn't a screw-up like Frenda, nor is she as frightful as her leader, Mugino. She enjoys bad movies and likes to tease others, Shiage in particular because of his reaction to anything sexually suggestive.

Level Upper Arc
Saiai and ITEM first appear in a Joseph's Coffee and Restaurant arguing about going into a public or private booth. In both anime and manga adaptations, she can be seen reading a magazine during their first appearance. In the manga they are arguing whether or not they should go to a pool since it's summmer, they are later seen to take notice of the Level Upper treatment program, which is being broadcasted all over Academy City.

Sisters Arc
They are later seen finishing up with one of their missions while continuing their swimming pool argument, when Shizuri gets a call to protect a research facility that is targeted by Misaka Mikoto. Shizuri orders Saiai to check the establishment and find out if the attacks were simply a diversion. Saiai observes this to be true, as she discovers and detains Nunotaba Shinobu who was trying to install certain emotions into all the sisters, however she failed as Last Order had acquired all the data, and stopped it's spread throughout the network.

Saiai is later seen to call Shizuri (who is in a fierce battle with Mikoto) that their part in the mission is done. She appears again after this telling Frenda on the behalf of Shizuri that she should be prepared for punishment.

Later events in the novels
In Toaru Majutsu no Index, Saiai is introduced in volume 15 along with her teammates.

After the events of the 15th volume she's seen with Hamazura Shiage and Takitsubo Rikou after their boss was supposedly killed. She is later hunted down by Stephanie Gorgeouspalace.

Ability
According to Teitoku Kakine, Saiai is a leftover from 'Project Mayday of Darkness' whose aim was to create a personal version of Accelerator's ability by using a similar pattern of ability operation. This was done by referencing the cognitive patterns of Accelerator himself in order to optimize the personal realities of certain espers taking part in the experiment. Though the details are not mentioned, Saiai only succeeded in creating an automatic self-defense capability that activates if she is attacked. Her ability is the Level 4 Offense Armor (窒素装甲), which she uses to control the nitrogen in the atmosphere to create a few centimeters of solidified nitrogen to act as a barrier. She can use this to attack and defend. Like Accelerator's AIM vector shield, the primary function of her ability is to create an armor of super-compressed nitrogen around her, she fights a sniper in volume 15 and Academy city's special sniper rifle is shown to have no effect on her other than to knock her backwards a little. Because of her ability, she carries around a small amount of nitrogen for use at all times.