Kamijou Touma/Chronology (Toaru Kagaku no Railgun)

Introduction
Although Misaka Mikoto is the main protagonist in the side stories, Touma occasionally appears as a recurring character. He is often shown helping people or being chased around by Misaka Mikoto demanding him to challenge her.

Level Upper Arc
Touma appears earlier in the anime eventually where he meets Kiyama Harumi and tries to help her locate her car before running away when she starts stripping (as is her habit) and leaving Mikoto behind with her. Touma later meets Mikoto after doing some shopping and having the eggs he just bought ruined. He then relents to Mikoto's demands and battles her. She uses her ability to control iron sand and attack Touma which he quickly dispels with his right hand. Despite Misaka's following 'trick' by grabbing his right hand to directly electrocute him, he is unaffected due to his ability and allows him to have an opening to attack her, though seeing her flinching when he raises his arm he throws the fight by faking that he was hurt. An irritated Mikoto then proceeded to chase him all night, trying to shock him.

He is later seen during the graviton bombing incident. Touma meets Mikoto in the Seventh Mist mall in which the latter quickly challenges him to another battle, which Touma points out that it was an inappropriate place for them to fight. Later during a massive graviton explosion, Touma uses his right hand to block the explosion from Mikoto and company after she failed to use her Railgun. They later meet again in which Mikoto asks why he let her take the credit for stopping the explosion, which he then replies that as long as everybody is alright it doesn't matter who gets the credit. This also infuriates Mikoto and takes her frustration on a nearby vending machine (an elevator door in the manga).

During Mikoto's attempt in obtaining information on the Level Upper, Touma meets her trying to rescue the thugs from her as he knows the thugs will get hurt when they cross Mikoto. This ruins her plans and she attacks him with her Railgun which is easily dispelled. She then proceeds to use her full power and conjures a powerful electrical storm to attack him, causing a massive blackout which is the beginning of Toaru Majutsu no Index. In the anime Touma does not appear in this scene.

In the anime, Touma also sees Mikoto on an electronic billboard happily prancing around with the swimsuit she wanted to wear. This is apparently his final appearance before he loses his memories.

Poltergeist Arc
In the anime, Index refers to Touma teaching her about the "3 second rule" on food during her struggle against a cleaning robot taking her donuts. Touma meets Mikoto for one last time before Mikoto's violin performance where he was searching for a lost Index. Here he has already lost his memory and acts polite and apologetic towards her as if he didn't recognize her. A flustered Mikoto then believes he came here to mock her. Touma comments that she looks quite good in her dress which causes an extremely embarrassed Mikoto to threaten him with a chair prompting Touma to run away, though this meeting relieved Mikoto somewhat as she has lost all her doubt and nervousness in performing her solo.

He is seen for one last time in the final episode of the anime during the end credits with Index giving her a drink, looking up at the sky smiling.

Sisters Arc
In the manga, Mikoto meets Touma near a vending machine after having the misfortune of getting his money eaten by it. Touma also meets Kuroko and one of the Mikoto clones. This scene coincides with the beginning of the Sisters Arc in Toaru Majutsu no Index; Touma's role during this arc is the same, though it is in Mikoto's perspective, Touma seemingly appears out of nowhere to help Mikoto with her problem with the Level 6 Shift.

There is also an expanded epilogue in the manga ("The Iron Bridge is a Sign of Love"), where Mikoto actually does make some cookies for Touma after he told her that homemade cookies are the best. She originally plans on visiting him at the hospital, but she meets Touma on a bridge on the way instead. Unfortunately, she is too embarrassed to give him the cookies. Mikoto tries to thank Touma for what he did for her, but she is unable to speak properly, so he misinterprets what she says. However, before he leaves, she tells him that she does not like being called "Biri Biri." After hearing that, Touma calls her by her name.

Silent Pary Arc

 * Main article:Silent Party Arc

Touma briefly appears on September 2, while looking at the sky during a lesson, after having scribbled a spoof of Index on his notebook.

Daihasei Festival Arc (Railgun)
Touma makes a brief appearance where he is seen buying drinks for him and Misaka since the lines are long. He is introduced to Shokuhou Misaki, the number 5, who apparently knows who he is, and asks if they really are classmates. They later agree on Mikoto's tendency to release electricity upon them, infuriating her. Later while in a Borrowing Race asking for a protective charm Saten Ruiko witnesses him running, she hesitates before giving him her charm. Touma takes it with his left hand, since he's afraid he'll negate the charm's "power". They agree to meet in front of a station in an hour so he can give Saten her charm back. Saten suggests that if he can't find her then if he could give it to Judgement's 177th branch office, they exchange names before heading their different ways. Later Touma is shown to have finished the race and is on his way to meet Saten at the station when he sees her and Xochitl as they exited from the laboratory. He heads in her direction and slowly climbs a fence to get to her and return the charm just as Xochitl is about to reveal the details and stops to smilingly listen. When he hears Xochitl speculate that the true goal is likely Misaka Mikoto. He immediately gives the charm back to Ruiko without much fanfare, and runs off to find her.

He arrives at Exterior just in time to see Misaka in her new form. He then get a mental debriefing on the situation from Misaki who suggests he hold her off if not stop her using the Imagine Breaker. As he charges at the distracted Misaka only to be rebuffed by a barrage magnetically controlled objects and lighting blasts. he is able to hold off the attack until she creates a large pile of magnetic controlled rubble, he is then saved from being crushed by the newly arrived Sogiita Gunha which he easily destroys with a single punch. He then ignores Touma's explanation of the situation, as they continue to argue about what to do when Misaka fires a lighting blast at each of them. Both teens not bothered by the incoming attacks and stop them in their own ways, they then decide to stop their argument and work together to stop her. As their fight against Mikoto continues she is becoming stronger due to her ongoing transformation. When Touma mentions that he wanted to come near Mikoto to check if he can negate her transformation, Sogiita says to leave it to him and uses Amazing Punch to create a path for him. He then procides to throw Touma at Mikoto and catching him in midair, Touma explains he can't fully negate her transformation because the source of power constantly sent her power and they can only held Mikoto back as an another person tries to stop her transformation. As she further transforms, Gunha asks what she is trying to do. As he ponders this he is stuck full on in the face by one of her attacks and is shot into a building. When Touma wants to check if he is okay, he jumps up and lands near Touma saying he is pathetic for letting his guard down and needs more guts or he will be in trouble, they then resume their fight against her.