Sanki Ai

Sanki Ai is an accountant serving Resanerié Sadis Dialine, as well as a student and debate representative of a School Garden school.

Personality
Sanki apparently only ever views things numerically.

Background
Initially Sanki was apparently an ordinary girl, but would come into the service of Resanerié Sadis Dialine, along with Tougyo Kea, Renka Ephilty and Shitatsuzumi Yoshiko, with Sanki acting as Resanerié's accountant. The five attended separate schools in School Garden and became the debate representative for their respective schools.

Toaru Kagaku no Railgun (light novel)
On the day of the entrance exams, she and the other debate representatives supported Resanerié as she executed her plot to take School Garden into the skies and make it independent from Academy City under her control.

As Misaka Mikoto began her rematch with Resanerié, she and the others moved to stop Uiharu Kazari from accessing the intranet and publicly revealing the data Yugure Kanaria had found. During the failed attack, as she witnessed Renka Ephilty crash, she intended to hide and secretly bring her allies back into the fight to attack their enemy when they thought they had won and let their guard down, but she was seen by Yugure Tsumebakei and attacked by her enlarged white blood cells.

Abilities
Sanki's ability is Plus Equipment, a telekinesis that forms a fine fabric with a skintight fit, apparently stronger than velcro and more easily attach to skin, and taking in more air than tying on a normal cloth, and as such, more effective as stopping bleeding than a bandage. It can also be removed without trouble as the ability can be deactivated at will.

She presumably has a degree of debating skill, being the debate representative of her school.