Kessai Kiyoshi

Kessai Kiyoshi (潔斎 雪紫) is a student of Tokiwadai Middle who appears in Toaru Kagaku no Railgun. She is the former roommate of Misaka Mikoto and a member of the Hasekura Clique, one year before the main story.

Appearance
Kessai has dark-colored hair, with an exposed forehead and prominent eyebrows. She wears the Tokiwadai Middle uniform.

Personality
Kessai seems to get along with Mikoto (addressing her as 'Mikoto-chan'), though she is secretly monitoring her for the Hasekura Clique.

Jailbreaker Arc
Some time after her battle with Shundan Kimi, a hospitalized Misaka Mikoto briefly thought back to her time with Ruri and Kessai while observing the interactions of her similarly hospitalized friends.

Kessai herself has yet to appear in the present day.

First Year Arc
Kessai joined Tokiwadai Middle in the same year as Misaka Mikoto, one year before the present, and became a member of the Hasekura Clique. When Mikoto achieved Level 5, her roommate moved out due to their own pride, allowing Kessai to be assigned to the same room at Mikoto, being tasked by Asato Kisa with monitoring the Level 5 for the clique.

During their first encounter, she walked in on Mikoto playing with Gekota toys but managed to talk her way out of being zapped to erase the memory. Not long afterwards, she sought to get a bonus Gekota hairpin for Mikoto as a birthday gift to get closer to her, bringing Asato and two fellow clique members to eat through a shop's entire stock of yogurt to find the prize. Although the group were eventually left unable to eat without having any luck, Kessai obtained the prize from Hokaze Junko's secret aid, though Mikoto turned out to already have one.

In early May, following a swimming class, she explained the circumstances surrounding Shin'enkouji Rurikakesu and Tokiwadai's three main cliques to Mikoto after mentioned her earlier encounter with the former. Leaving for her club, she accidentally left behind an accessory, which Mikoto noticed after she had left, and in trying to contact her to return it during the day, encountered the three clique leaders and a few others. Kessai had a phone conversation with other clique members regarding Mikoto, before receiving her accessory back in the evening, when both had returned to their room.

At some point after the switch to summer uniforms, Kessai witnessed an argument between Mikoto and Shokuhou Misaki. After listening to Mikoto describing her first encounter with the other Level 5 and thinking about the circumstances while they walked down a street, the pair encountered Ruri who accompanied them to Vending Machine 7116.

As tensions were rising between the Hasekura and Mikagami Cliques over an alleged attack, Kessai was nearby when a group of Mikagami clique girls were attacked by an unknown assailant, with one injured, and was attacked by Urui Aika and Asakura Olivia Moa under the presumption of being the culprit. Although she initially escaped them with a smokescreen, she was cornered in an alleyway. Before they could continue their attack, Mikoto arrived and was willing to take them on despite the repercussions of interfering with an inter-clique conflict (which Kessai tried to warn her about), however Ruri appeared and managed to defuse the situation. Afterwards, Kessai had a chat with Mikoto and Ruri, informing the former of the aforementioned repercussions, though Mikoto was not too concerned.

A number of days later, with tensions continuing to escalate despite Hasekura Reiri's orders not to fight, Kessai talked about the situation with Mikoto. Later on, after Mikoto had got involved in another clique fight and clashed with girls from the Hasekura clique, Kessai complained after she returned, after watching a video of Hasekura's Paris demonstration.

When Hasekura came back, she contacted Kessai to arrange a meeting with Mikoto so she could get her help in finding the truth behind the clique conflict, with Kessai initially apologizing for Mikoto's previous actions. A week afterwards, she was accompanying Hasekura on Asato's orders while the aides were with Shokuhou, in case something happened. As Hasekura met Sha Danshan, they came under attack, with Kessai throwing up a smokescreen. Although the assailants withdrew before the smokescreen fully dissipated, the evidence they left behind put the girls on the right track.

Abilities
Kessai's unnamed ability appears to allow her to discharge steam from her body. As a student of Tokiwadai Middle, it can be presumed to be at Level 3 or 4.