Kaoru has black, curly hair, black eyes, an average ebust size and her body is tall as the generally of the teen girl's height.
Kaoru is a tough and hardworking girl who is both lively and unpredictable.
She also has a habit of teasing and hitting Junichi Tachibana at seemingly random moments. She is also the main target of Junichi's perversion and she is also seen with Masayoshi Umehara (Junichi's best friend). She works part-time as a waitress at a family restaurant and sometimes in other part-time jobs to help her mother maintain their ability as a two-person family to live independently. Consequently, she is totally against it when her mother dates another man.
Taking the time days before their first date. Junichi accidentally meets Kaoru during her other part timer jobs as a seller. While in the middle of talking, Kaoru and Junichi (unbeknown to Kaoru) think about where should they have a place for the first date. This OVA end with Junichi helps Kaoru with her selling.
Kaoru and Junichi spent their time for summer holidays by taking a two-days trip. They obtained the money from their temporary job as Inago Mask stageplay (which also resulted with only half pay due to Junichi's actions). They take the bus trip, and end up lost due to Kaoru's idea of camouflaging her stuff to look like a couple is sleeping, tricking the investigator into thinking that they were already on the bus.
They were soon helped by a truck driver, being sent into an inn. Humorously, due the inn seeming to be haunted, Kaoru is scared. The next day, they walk for long and soon stopped at the bus stop, taking rest in there. After the bus stop is revealed to be unused, they soon leave.
In the end of the trip, they are founded by Umehara because of his sushi chef training. This arc ends with Kaoru sit on Junichi's thigh again like the beginning of the first arc to fix his drawing and tell him that is their relationship (which makes Junichi so shy at the first time)
Taking the time when Kaoru and Junchi were sleeping in the inn. She doesn't realize that her clothing are opened and being seen by Junichi. Junichi watched her sleeping and judged it as rude sleeper. Half awake, Kaoru sees Junichi is getting close to her, wondering and end up judging the situation as Junichi will rape her. But actually, Junichi is fixing her blanket. She glad and thanks Junichi without his notice.
In Kaoru's route, she is portrayed as Junichi Tachibana cheerful friend. Loves to tease him and he considers her a "bad friend". In her route, she kisses Tachibana a lot and he wonders if she's just messing with his head. She's not.
Kaoru's mother is getting married to another man that this depresses Kaoru and Junichi Tachibana becomes her emotional support throughout. On Christmas, they spend the night in Junichi's room. While in bed, Kaoru climbs on Junichi, shares a kiss, and tells him how their relationship parallels that of her parents. The morning after, they can be seen riding a bike together and then meeting with Kaoru's family some time afterwards. They'll be "bad friends" forever.
Kaoru and Junichi are both in college, sharing a place together. She cuts his hair. She realizes they'll be "bad friends" for a long time to come.
Keiko is dumped again and Junichi encourages her. Keiko asks him to be her boyfriend. Kaoru punches him in the face and yells that there's no other girl for him but her.
If Junichi stoods her up on Christmas, she forgives him. She's crushed but forgives him by throwing him in a river during winter. Junichi floats away while she yells that she still loves him.
- The name Kaoru means "fragrance, fragrant" (薫).
- Kaoru's surname Tanamachi means "shelf" (棚) (tana) and "town" (町) (machi).
- If one follows Kaoru's arc, she may share the distinction with Mao Mizusawa, the main heroine for Kimikiss which serves as Amagami's spiritual predecessor, for being a childhood friend to love interest for the main male leads. She would be followed by Haruka Niimi from Photokano if one is to follow her arc as well.
- Kaoru is called by the nickname "Sex Hair".
- In Episode 5, her ear bite on Junichi Tachibana's ear may be referenced to the series' title (Amagami means "nibble/gentle bite").
- Kaoru is the only person who was not surprised when Tsukasa Ayatsuji showed her "dark side" to her classmates for the first time. Maybe it's because her usual self matches Ayatsuji's dark side, so there's no one in the class, even Tachibana Junichi, see it suspicious.
- In SS+ Miya Tachibana arc, this fact can be proven when Tsukasa and Kaoru are trying so hard to expand their breasts in the special onsen and they even do evil laugh together.