That idiot sure is having fun. You've seen him clenching his left hand, right? It's a long time habit of his. When it happens, he usually messes up even the simplest things.
~ Chifuyu to Maya about Ichika's habit.
Chifuyu Orimura is a supporting protagonist in the light novel and anime series Infinite Stratos. She is Ichika Orimura's older sister as well as his homeroom teacher. She is the former IS Representative of Japan and a Mondo Grosso champion before she retired. Additionally, she is a close friend to the IS creator, Tabane Shinonono.

She is voiced by Megumi Toyoguchi in the Japanese version of the anime, and by Luci Christian in the English version of the anime.


Chifuyu is a tall woman who has long black hair, which is split into parts in a similar manner to Ichika's. She's also said to possess good fashion sense and the way she carries herself is seen as being regal, like a high-borne lady. Her normal IS teaching outfit consists of a formal white shirt, with a black business overcoat and matching skirt, green tie, stockings and high heeled shoes. For IS Training, she would change into a white jogging suit.

In the light novel, other characters have often said that she has a very good figure and is compared to a model by her "worshippers" on a regular basis. Even Ichika tends to get a little embarrassed when he sees her in clothing that accentuates her figure, such as the black bikini she wore to the beach. 


Chifuyu is a very stern and strict woman, even to her brother, as seen when she tells Ichika to call her Orimura-sensei instead of his more familiar Chifuyu-nee ('Big Sis Chifuyu'). Chifuyu is also a very prideful and stoic woman, having cared for Ichika since she was a teenager and he was a child and therefore forced to essentially be a mother to him. Also, being a very skilled IS instructor, Chifuyu has stated that what makes her strong is her little brother Ichika, for it is him who gives her strength.

Despite her strictness, it seems she also has a far more casual side, that of a normal woman who enjoys drinking alcohol (which apparently even Laura Bodewig does not know of, despite having trained under her for a full year), and messing with her juniors. She acts very differently at home, which is why Ichika was caught off guard so much the first day, as she doesn't do much housework, leaving Ichika to tend to things. She also does like to tease others on occasion, especially Ichika, who is very susceptible to her. She is also very protective of Ichika, as he's the only family left after their parents abandoned them. She was the one to enroll him into the I.S. Academy almost immediately after it was confirmed that he had the ability to pilot the female-exclusive IS units.

Some of the characters noted that her closeness with him seems a little suggestive which only serves to incur a bit of her wrath when they tease her about it. More so, the girls noted that the interaction between her and Ichika during certain situations, such as Ichika was seen blushing profusely after seeing his own sister in a rather revealing black two-piece swimsuit, however this could simply be because he was embarrassed of seeing her dressed in a swimsuit. There was also their initial impression on the massage incident, but that was just the girls jumping to conclusions. Through this, Chifuyu is highly aware that Houki, Cecilia, Charlotte, Rin and Laura are in love with her younger brother Ichika.

In battle, Chifuyu is very level headed and even relaxes as she would smile and mock her opponent. This confidence seems to come from her former title as world strongest. She didn't even show any worry or fear about facing an IS without one. As well, despite having allowed the personal IS student to fight in real battles, she deeply regretted that she had; accepting that it was an unforgivable action for a teacher and adult.

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