Tetsumou

Tetsumou (鉄網) is a minor character in the Toaru Majutsu no Index series. She is a member of BLOCK, and with her esper abilities, uses it to find traitors in the group. She is the second named member of her faction to be put out of commission after Yamate, who was killed by Etzali.

Appearance
She wears her light colored hair short like a pixie cut. Her gloomy nature well seemingly fits her petite appearance. She wears a sailor uniform of an unknown school.

Personality
She has been described as a gloomy girl, a stark contrast to all of the serious, professional soldiers that she has to deal with.

Background
It is unknown how to Tetsumou ended up in BLOCK, though it is most likely that she got in through her power. This is evidenced by her stating that she is only good at reading people's minds and that Saku Tatsuhiko wasn't interested in her after she collapse after having her hand explode.

Battle Royale Arc
In her debut appearance she is asked by Saku Tatsuhiko, the leader of BLOCK, to verify the identity of the people present in the room with her ability before BLOCK's operation can begin. After analyzing Saku and Teshio Megumi, the latter's past disturbing her enough for Megumi to advise to stop reading her mind, it was Yamate's turn. However, since Yamate was already dead and that his appearance was borrowed by Etzali, he was forced to make a quick solution before Tetsumou finds out he is an impostor. As he had played with hand cream a bit before, he had spiked it with a small quantity of liquid explosive. Etzali pretended to lose his grip on the hand cream container, forcing a minor grunt to pick it up for him.

Etzali goes to it and has him get analyzed by Tetsumou first instead of him, rubbing the dangerous explosive on his hand. As Tetsumou touches his hand to read his mind, their hands suddenly burst into flames, and she loses a few fingers of her right hand. The shock and blood loss then renders her unconscious, which prompts the grunt to reach for the first aid kit, but Tatsuhiko executes the grunt despite his pleas, believing him to be the traitor inside their group all along. Noticing that Tetsumou could no longer function as a polygraph, Saku shows no interest in her condition, saying that there isn't any time to "find a replacement" and instructed some of his men to take care of her body.

Etzali regrets the result, but he also realizes that if he hadn't used such a measure, he would have been killed and no one would be able to stop BLOCK's revolt. It is unknown what exactly happened to Tetsumou afterwards, but it is known that Academy City's facilities can perfectly treat wounds far worse than a few lost fingers without even leaving scars.

In anime adaptation, the scene where Tetsumou is tasked in rooting out the traitors in BLOCK was cut and Tetsumou's Skill Polygraph is never featured. Instead of having her fingers blown off as the result of Etzali's actions, she is instead caught in the Six Wings attack.

DRAGON Arc
In the anime, she was shown to be part of the new team that was established after the events of the Battle Royale Arc.

Abilities
Her ability is named Skill Polygraph (意見解析(スキルポリグラフ)) and allows her to verify the profile of a person as long as she holds hands with her target. The "voice" that she uses to read the profile of her target is not her regular voice but an "inhuman, mechanical-sounding" one. Along with their basic information, such as name, age, and occupation, she can even read important facts that have happened to them in their past.

Quotes

 * (To Saku Tatsuhiko, from Volume 15): "Reading people’s minds is all I’m good at.”