Kamiya Kaoru (神谷 薫 Kamiya Kaoru?) is the teacher from a kendo school from Tokyo called Kamiya Kasshin-Ryū. The school starts to lose all its students when a thief from the city starts killing a large number of people and claims to be the "Hitokiri Battōsai (斬り抜刀斎?) from the Kamiya Kasshin-Ryū". Kaoru encounters him but before being killed by him she is saved by the real Hitokiri Battōsai, now a wanderer, Himura Kenshin, to whom she offers to stay in her dojo as she notes Kenshin is a gentle person instead of a hitokiri. As the series continue, Kaoru develops strong romantic feelings for Kenshin, who is constantly haunted by the wrongs committed in his past, and believes he does not deserve happiness.
The primary instructor of the Kamiya Kasshin-Ryū fighting style developed by her late father, Kamiya Koshijirō, Kaoru inherited a small dojo from her father after he was killed during the Seinan War and operates it by herself.
At the beginning of the story, she has no students and she is likely to lose the dojo until Kenshin appears and helps her. Naturally, she is independent, possessive, compassionate, courageous, feisty, strong-willed, and a great fighter to boot- with only the occasional mood swing. Kaoru is also known for her bad cooking which is disliked by her friends and family and her ability to see the good in others.
Though she is short tempered and possessive, Kaoru is incredibly selfless. Although most times she is seen fighting against Myojin Yahiko, they care about each other and Kaoru sees him as the succesor of the dojo. She is considered naive to be so trusting, but she has the maturity to handle the consequences. Kaoru's beliefs are held strongly and proudly, almost stubbornly, particularly her beliefs in the sword.
She falls in love with Himura Kenshin right from the beginning of the series, and continued to do so even after learning of his past crimes. One of Kaoru's biggest fears is that Kenshin might someday return to wandering, leaving her to be alone again. She gets jealous whenever another girl is also interested in Kenshin, such as Takani Megumi to whom she often argues but in the end of the manga ends admiring her. When discussing with Megumi she is often compared to a Tanuki due to the way she acts.
Kamiya Kaoru adheres to her father's ideal of "Swords that give life," which teaches that swordsmanship should be used not to kill, but to protect. This belief is a slap in the face to many swordsmen, who advocate that a sword is for "mastery and death," and nothing more. Himura Kenshin, however, feels that her beliefs should, in fact, become reality.
Kaoru is a practitioner of the Kamiya Kasshin-Ryū (神谷活心流? Kamiya Kashhin-Ryū). The primary weapon of a practitioner is a wooden bokken. A bokken is generally considered to be a more advanced weapon in kendo practices and can deal more severe damage, hence the bokken is likely reserved only for masters of the Kasshin Ryu style or for those who are considered advanced in their studies.
As a teacher of the Kamiya Kasshin-Ryū, Kaoru mastered the successions technique. In the first one, Hadome, Kaoru crosses her arms over her head and catches the blade of the opponent with the back of their hands. This allows her to maintain their grip on her sword while catching the opponents blade at the same time. However, if properly used, it can be chained into Hawatari Kamiya Kasshin-Ryū's offensive succession technique. It is a counter-attack and can only be performed after a successful use of the Hadome technique. From the Hadome position, Kaoru twists her wrists, thus stripping the weapon of their attacker away from their wrists.
Techniques of this style also are meant to be performed with the weapon broken. With Tsuka no Gedan: Hiza Hishigi (Handle Attack, Knee Crush?) Kaoru dive-lunges at her opponent's knees, bringing the hilt against their knee. She uses this attack to defeat Honjo Kamatari.