Resanerié Sadis Dialine

Resanerié Sadis Dialine (レザネリエ＝サディス＝ダイヤライン) is a third-year student of Tokiwadai Middle School, the school's debate representative and head of its equestrian combat club, as well as the young Empress of the Dialine Empire in Eastern Europe.

Appearance
Resanerié has shoulder-length red hair, with jewelled tiara worn on top. As a student of Tokiwadai, she wears the school's uniform, with thick leather riding breeches on her legs.

Background
During her time in Academy City, she acquired the loyalties and services of four ordinary girls, separate from her retainers back in the Dialine Empire, who would be the debate representatives of the other four schools in School Garden, with Resanerié being Tokiwadai's debate representative. Tougyo Kea served as her attorney, Renka Ephilty as her maid, Sanki Ai as her accountant and Shitatsuzumi Yoshiko as her chef.

At some point in the past, Resanerié's beloved horse Bistorio (ビストリオ) broke his leg in a training accident and was forced to retire. Considering that his treatment costs and genetic value were not worth it, without Resanerié's consent and against her wishes, the adults removed his medical equipment and denied him further medical care or euthanasia, letting him die in pain. Besides her rage and sorrow at having lost her partner, Resanerié realized that the adults did not treat humans any better, and the same could happen to any of the students, with the possibility of something happening to her to preserve the secrets of esper development when she was due to return to her own country. She subsequently devised a plot to take School Garden to the skies away from Academy City and have everyone in it declare independence, which she saw as the only way to protect themselves from any such fate.

For some time, Resanerié utilized the resources at her disposal to secretly prepare the underground foundation necessary for her plot, including the propulsion and reinforcement necessary to make School Garden airborne and factories to supply the population with food. At same time, she and her servants would plan and lay the psychological groundwork in their positions as debate representatives.

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

Abilities
Resanerié's ability is Level 4 Crimson Manager, which allows her to manipulate rust. She is capable of rusting a rustable target within her proximity, and can also telekinetically control rust to move rustable objects with considerable force and speed, accelerating the rusting of those objects in the process.

Resanerié is skilled in the use of the, both on foot and on horseback, wielding it one-handed (her other hand for the reins). She can supplement its destructive power and speed with her esper ability,  but at the risk dislocating her shoulder without stretching first to loosen up the joint,  and at the cost of her halberd rusting and eventually crumbling away (even with resistant stainless steel and titanium alloy, the latter estimated to not last 10 minutes).

Being the captain of the equestrian combat club, she is presumably skilled at riding a horse in addition to horseback combat, though she has lost her partner Bistorio. She is also skilled at debating and psychological manipulation, illustrated in her position as Tokiwadai's debate representative and her manipulation of School Garden's students during her plot. With the latter, she also wielded a megaphone that besides producing sound also spread an itching chemical to further agitate her targets.