Ouka is teenage girl of average height with an extremely well-endowed figure and in terms of beauty is described as "perfect" by Kanade Amakusa and other boys at her school, in spite of her behavior and status in the Reject Five. Ouka has long, dark-brown hair that flows down her back and passes her hips and has a pair of round light purple eyes. She wears a pink headband with a big bow on the left side of her head.
She has been seen in two outfits; the standard girl's uniform, but has unique style she unbutton the bottom part of her shirt, revealing a bit of her stomach also wears a pair of brown boots.
When outside of school, Ouka would usually wear a long-sleeved purple sweater with pink colored skirt. She has also been seen wearing a pink swimsuit when at the waterpark.
She is a cheerful, hyperactive, airheaded and most of the time a happy-go-lucky girl. However, despite that, she is also very shy as shown when exposing her underwear to certain people such as Kanade makes her embarrassed. She also recalled her mother's words of only crying in front of the man she loved.
She shows that she really has a girly side as she was flustered when Kanade accidentally fondled her but was relieved he didn't remember doing so. She later got scared at an amusement park ride and was touched when Kanade carried her. She also showed this side again as she blushed when Chocolat brought her closeness with Kanade.
She has a tendency to refer people with cute nicknames like Kanade as "Amacchi" and Furano as "Furanocchi". It is revealed that she is best friends with Konagi, a girl who is placed as the third in the popularity rankings, and they continue to be on good terms despite Ouka being in the Reject Five herself.