Kaitabi Hatsuya

Kaitabi Hatsuya (介旅 初矢) is a minor antagonist from the Toaru Kagaku no Railgun side story. A Level 2 esper student in Academy City who felt a strong sense of distrust against the authorities, he used the Level Upper in a series of attacks against members of Judgment as the Graviton Bomber.

Appearance
He sports glasses and has grayish-brown hair. Many of his appearances have him wear his school uniform while wearing his headphones listening to the Level Upper. He also carries a satchel with him containing many aluminum spoons for use as bombs.

Personality
He is fairly weak and doesn't fight back when confronted, but he holds grudges on those who have wronged him. He is cunning when exacting his revenge, even willing to hurt innocent people in the process.

Background
Before attaining the Level Upper, he was often bullied by his schoolmates and other delinquents. Upon seeing his experiences left unresolved, he began to develop a growing sense of resentment towards Judgement because he felt that they were never there on time to save him from his attackers.

He later acquires the Level Upper and puts it into constant usage, eventually manifesting enough power to have characteristics of a Level 4. Despite this, Hatsuya is continually abused by his tormentors, causing his sentiments against Judgment to worsen. Hatsuya eventually decided to take his revenge on Judgment with his boosted powers. At first, he used aluminum cans in waste bins as bombs, however he eventually used more deceptive tactics such as putting aluminum inside mundane objects such as dolls and bags. Before his introduction he has struck five times, the latest causing no casualties.

Level Upper Arc
His activities are first introduced during Misaka Mikoto's brief tenure as a member of Judgment. At this point he has already caused five graviton bombings, the last one having no casualties and having Judgment gain a clue on his abilities. In the Toaru Kagaku no Railgun anime, Mikoto witnesses Hatsuya being assaulted by thugs but after he accidentally bumps into them, after stopping their assault Mikoto prevents herself from attacking them and asks if Hatsuya is alright, here he tells her that she should've been quicker and promptly leaves her. Later, another graviton bomb explodes in the Green Mart convenience store and severely injures a member of Judgment after protecting a civilian.

During the height of the bombings he has already injured nine members of Judgment, even with the cooperation of Anti-Skill they are still unable to find any leads on him. Before his last attack he is continually abused by delinquents and schoolmates and once again blames his condition on Judgment. During the preparation of his next attack he uses a frog doll as a container for his bomb which he has on his maximum output. He attacks on the next day, after seeing Uiharu Kazari a member of Judgment enter the Seventh Mist mall, he gives the frog doll to a girl (who both Mikoto has met previously) and asked her to give it to Kazari.

The bomb goes off and nearly engulfs Kazari, Mikoto (after failing to use her railgun on the bomb) and the little girl, have it not for the efforts of Kamijou Touma using his power to stop the explosion from affecting them. Having thought that his plan was a success, Hatsuya goes into an alley gloating that he can now take on members of Judgment and the delinquents that attacked him but he is attacked by Mikoto who tells him that he has failed in hurting anyone with his bomb, he tries to retaliate using a spoon but it is blown away by Mikoto's railgun, knowing her identity he rants on how he always ended into situations like the one he is now and blames people like Mikoto, Judgment and people with power for his fate, at which point he is punched in the face by Mikoto. He is later confronted by Shirai Kuroko telling him why Mikoto hit him and that she used to be a level 0 before working her to become a Level 5 and says that regardless of her level she will still try to stop him.

Later it is uncovered that Hatsuya is only a Level 2 and that he shouldn't be able to create such destructive power, because of this discrepancy the existence of Level Upper is confirmed by Judgment. Like all Level Upper users he falls into a comatose state.

He appeared during the rampage of the AIM Burst in a room in Mizuho Medical Institute, like all users of the Level Uppers he goes into painful convulsions while being unconscious. His thoughts are later seen within the AIM Burst lamenting his fate and he later calms down after the sound file that is the treatment for Level Upper is played all over the city. He probably regained consciousness like the rest of the Level Upper users, but he is not seen with the rest of the users in the special class for them.

Later, he walks past the students he used to always lecture (about never giving up) and this time ignores them. They notice this difference, as well as the fact that he now wears a headband. He tells them that he was cheered up. He recalls experiencing the power of Misaka Mikoto's railgun and, inspired by that power, wills himself to try harder to reach the same high position. One student, reluctantly 'inspired', gets up and tells the other student to go back to school. She tells him that the shirt he's wearing (to match Sogiita Gunha's shirt) doesn't suit him so he should stop wearing it.

Abilities
His ability is Synchrotron (量子変速 (シンクロトロン) ). It allows him to accelerate s (the particle that mediates the force of gravitation) and use aluminum objects as explosive devices through extreme compression and a subsequent release of energy. The Level Upper version of this ability (categorized as a Level 4 ability) can create a sizable explosion from a small amount of aluminum.

Trivia

 * His music player looks similar in design to an.
 * s are hypothesized elementary particles in quantum mechanics that supposedly govern the force of gravity. There is as of yet no proof for their existence in our world, but seems to have been confirmed to exist in the world of Toaru, or at least inside Academy City, as seen with the graviton panels used at Exterior.

Quotes

 * "What are they doing? What the hell's up with Judgment? You guys are all useless! I have to do everything by myself! Just wait and see...!"
 * "This is the dawn of a new world... A world where I look after myself..."
 * (To Mikoto) "It's always like this. No matter what I do, I just get beaten back down. I'll kill you. People like you are at fault here! Judgment is, too! Everyone with power is like you!"
 * (His thoughts within the AIM Burst) "No matter how hard I work in this city, a wall called 'ability' keeps getting in the way. That miserable life, being stepped on... Everyone just pretending they didn't see it..."