Ichika Orimura is the main protagonist of the anime and light novel series, Infinite Stratos. He is the younger brother of Chifuyu and is revealed to be the twin brother of Madoka Orimura. He is also the only male to operate and control an IS.
Ichika is friendly and kind to anyone he meets. He is also kind, considerate and polite to those he meets. He cares for his friends greatly and protects them when they are in danger. Due to his kind personality, many female characters have come to fall in love with Ichika and make attempts to have him for themselves. However, when he first arrived at the IS Academy, Ichika felt extremely nervous and uneasy being the only male and hate getting attention. Ichika is also extremely dense and clueless regarding when girls harbour romantic feelings for him, but on rare occasions he seems to slowly become more aware (most likely implied towards Houki). While Ichika can be annoyed, nervous and extremely confused when the girls are mad at him, he knows how to defend himself against others whether they are engaged in a physical fight or if someone is simply being rude and unfair towards him. However when they girls become mad at him, Ichika is in fear of his life as their anger can get severely out of control and completely doesn't understand when they think such ridiculous and eccentric thoughts and ideas about him. Ichika is also quite intelligent as while in the beginning he still didn't understand the IS, being the first and only male in history to operate one, he continues to study and learn more about and is also a quick learner.
Houki is Ichika's first childhood friend. Ichika and Houki first met each other when they began attending Kendo classes together and have always been the same classes together in Elementary school from the 1st to 4th grade. Houki has always had romantic feelings for Ichika, but is nervous when expressing her feelings and uses her short temper to hide how she really feels. When a important Kendo match was approaching, Ichika promised to become her boyfriend if Houki won the match, but at the same time, Houki's older sister introduced the IS machines. Due to this, Houki's family was put in the protection program if the machines were used for wrong and evil purposes and thus Houki and Ichika have been separated. Six years later, Ichika and Houki are reunited when Ichika is enrolled at the IS academy being the first and only male to be able to use an IS.
Ichika, due to his nature, sees Houki in the light of an extremely strong childhood friend of his. He is willing to do things for her that he probably might not do for others. However, before the events of the Shinonono festival (at the end of episode 12 season one), they had practically dated and nearly kissed, implying that he may have some sort of emotions regarding Houki. Of course, Ichika's kiss was comically obstructed by Cecilia, Rin, Charlotte and Laura, causing him to run away with a comical worried face saying "he is going to die".
Even after years apart, Houki still has strong romantic feelings for Ichika, but still has problems expressing how she truly feels about him, but still makes the effort to show her feelings. Houki's best efforts are cooking her bentos for Ichika, much to his pleasure. In the beginning upon their reunion, it was awkward for Ichika and Houki, unsure of how to approach each other and soon Ichika became somewhat afraid of Houki due to her short serious temper, espically upon finding out she was his original roommate. Despite Houki's temper, Ichika still cares a great deal about her and makes attempts to reconnect with her after years apart, feeling bad as he doesn't remember much of their past since their separation. Several times throughout the series, Ichika seems to become more aware of Houki's feelings and appears to feel the same way towards her.
When Ichika and Cecila first met, Cecila took an immediate dislike to him, believing he was unfit to be an IS user and believed he was a commoner and treated him as if he was useless. While Ichika ignored her insults in the beginning, he eventually grew annoyed by Cecila's arrogance when he was selected to be the representative of their homeroom class. Cecila was immediately against the decision and soon they both agreed to have a duel to decide. During their duel against each other while Cecila held the advantage against Ichika, he quickly learned how to control and operate his IS, greatly impressing her. By the end of the duel although Ichika lost to Cecila, she found herself unable to think of anything else other than Ichika, realizing she had developed romantic feelings for him. Since then, Cecila has become more kinder to Ichika, giving the position for class representative to him and improving their relationship. She officially becomes the second person to have Ichika for herself.
Rin is Ichika's second childhood friend. Shortly after Houki moved away, Rin transferred to Ichika's school and they soon became close friends. However, unknown to Ichika Rin has secretly had romantic feelings for him ever since he protected her from four bullies. Ichika and Rin continue to have a close friendship, both well acquainted with each other's families as Ichika would regularly eat at Rin's family restaurant. However, prior to the series they were separated for a year until they were reunited when Rin surprised him upon transferring to the IS academy. Ichika is delighted of meeting Rin again after their one year separation and Rin officially becomes the third person to win Ichika for herself after her feelings for him are revealed. Rin becomes mad with Ichika upon finding out he and Houki are roommates which leads the pair to have a duel with each other. Rin is an independent person as she doesn't like to be seen as a damsel in distress, proven during her match with Ichika, wanting to be seen as a powerful person, most likely to prove herself worthy of Ichika. However, Rin can be seriously jealous and similar to the rest of the girls can have a serious fiery temper in regards to misunderstood situations with Ichika or who he really likes in return. Although despite Rin's temper, Ichika remains close with her and views her as a good friend as she was one of the few rare people Ichika could talk with since her transfer to the IS Academy.
Originally, Charlotte masqueraded as a boy when she first began attending the IS academy and became Ichika's new roommate. Ichika and Charlotte began to develop a close friendship as she helps him to better understand the IS machines and how to properly work on them. Ichika soon became the first person to learn Charlotte's secret, but upon learning the reasons forcing her into the situation regarding her family, Ichika promises to keep her secret. Soon, Charlotte begins to develop romantic feelings for him and is constantly nervous whenever they are together, especially when they are forced into embrassing situations. Eventually, when Charlotte revealed her true gender to everyone, Ichika created a special nickname for her, calling her Charl, much to her delight.
Orignally, Laura hated Ichika, blaming him for his older sister leaving Germany. Ichika strongly disliked Laura as she nearly killed Cecila and Rin during a practice match and was determined to beat her during the official matches competition. He also became angered when her IS went out of control and took a new form, copying his sister's fighting skills, he was determined to stop her for good. Due to this, the relationship between them soon changed when he managed to save her and revealed how he was truly strong. Since then Laura has developed romantic feelings towards Ichika, saving him from an attack from Rin and proceeded to kiss him, claiming Ichika as her bride. Throughout the series as Laura's feelings for Ichika increase, she begins to slightly change, becoming more feminine to gain his attention and affections. Laura also constantly protects Ichika whenever she has the chance, saving him from several attacks by love rivals or enemies.
Ran Gotanda is the younger sister of Ichika's close friend Dan. Ran has romantic feelings for Ichika and makes herself pretty for him whenever Ichika visits her and her brother, not wanting to make herself unpresentable. Since Ran doesn't the IS Academy, she can only meet with Ichika on a few occasions. Ichika is happy to see Ran and views her as a good friend, unaware of her romantic feelings for him. Ran's brother Dan is aware of her feelings for Ichika.
Tatenashi's younger sister. The IS Representative Candidate of Japan and Class Four. He asked her to be his partner during the tournament at the IS Academy (Tatenashi asked him to do it). Since people usually are not nice to her, she took it as a bad joke and slapped him. After that event, she started to fall for him, so she finally accepted his petition. She appears in Volume 7.
Her feelings for him seem to be connect to love for heroes. As such, she view Ichika as her hero (someone who will always be there for her and protect her). At the end of Volume 7 and episode 9, she confesses to him. But because they were talking about anime, she believe (which is most likely true) that Ichika thought she meant anime and not him.
She behaves like the other girls who love him do. Shy when he compliment her looks, but will become angry with him when he compliment another girl. Although, compared to the other girls who would use their IS or a real weapon on him, Kanzashi hasn't yet (but doesn't hide the fact that she is angry with him).
She was assigned by the headmaster to protect him and prevent his IS from being stolen.She enjoys teasing or flirting with him in a manner that makes him very uncomfortable. Throughout Volume 6 it is shown that she is becoming more mindful of Ichika, even thinking of him on random occasions. In Volume 7, she trusted him enough to ask him to help her little sister, Kanzashi. She later questioned her reasons for doing so before admitting to herself that she wanted to flirt with him. At the end of Volume 8, her feelings for Ichika take a step further when she reveals her true name (Katana Sarashiki) to him, which has a special significance in the Sarashiki family, indicating that a certain level of affection has grown between them (at least from her side). Afterwards, their relationship started changing with Tatenashi becoming more shy around Ichika, while Ichika on the other hand started becoming more comfortable around her. The other girls (including Kanzashi) even worried if the two them were dating each other. While both of them denied this claim, Ichika did admit that he enjoys being with Tatenashi, even pointing out her positive traits compared to the other six girls.
- Although not officially confirmed, many believe Ichika has romantic feelings for Houki.
- Houki is the first character to confess her feelings to Ichika (second one being Kanzashi). However, the first time she did so, her confession was rendered inaudible by the fireworks. The second time she did, she was asleep when she said it, but Ichika didn't hear her well and quickly noticed she fell asleep.
- Out of all the female characters, Ichika has only ever kissed Laura.
- Ichika has been roommates with Houki, Charlotte and Tatenashi.
- He is voiced by Josh Grelle who is well known for his roles as Zen Wistaria, Masamune Makabe, Touya Mochizuki, Azusa Asahina and Yamato Naoe, and Sadao Maou.