|Occupation||Middle School Student|
|Family and Relatives||Nadeshiko Katou (mother)|
|Seiyuu||Eriko Nakayama (as GUNTA)|
Karen is a short girl with brown hair tied with ribbons into twintails. She also has brown eyes like her sister, Otome. Unlike her though, Karen appears to have a much bigger bust, despite the age difference.
In the visual novel she's mentioned to be one year younger than Otome and since they went to the same Junior High all three of them used to hang out together. Otome also mentions she's studying to try for their school, while Makoto reveals she is a big sports player but is bad at studying.
In both Summer Days and Shiny Days, Karen has two endings titled "Karen's Summer" and "Son in-law Ritual".