Kanade is a classmate of Ouka's as well a fellow member of the Reject Five. Both are good friends, though Ouka's tendency to mock his problems because of the Absolute Choice can get on Kanade's nerves. She often notes that while he likes to do weird things, it's nothing more than a big lie and tries to help him sometimes. Ouka has even given him the nickname "Amacchi" which he doesn't seem to mind, showing he has no problem with her.
Throughout the series, it is highly hinted that she has romantic feelings for Kanade, as it is shown that Kanade is one of the few, if not the only person who can make her truly feel embarrassed. For example, although she is unfazed by others that witness her usual antics of doing somersaults and kicks that exposed her panties, she is completely flustered and blushes upon realizing that Kanade was the one that had looked at her underwear even having problems talking to him the next day. Kanade was oblivious to her affections and often gets confused by her sudden changes in demeanor when this occurs.
Nonetheless, Kanade cares very much for Ouka, which was shown while they were at the water park and they go to a haunted house ride where Ouka gets scared and starts to cry. He carries her through the ride, causing her to feel glad Kanade cares that much for her. In return, he blushed when talking to her about the experience with the two staring at each other intently before their moment is ruined by Seira Kokubyakuin. She also blushed when Chocolat made note that Kanade cares about her and comforts her whenever she's down. She was very surprised and worried when she found Kanade and Chocolat hugging as well as when Kanade admitted that he liked Chocolat on an open microphone at the park but was relieved it wasn't in a romantic way.
Is one of Ouka's classmates another member of the Reject Five. Ouka considers Furano as one of her close friends and has given her the nickname "Furanocchi", which the latter doesn't seem to mind.
Unlike Kanade, Furano finds Ouka's antics to be very amusing and has shown concern for her on occasions, they have a friendly relationship despite Furano's tendency to mock everyone.
Despite that, Furano is secretly envious of Ouka's larger chest while Ouka seems unaware of this fact. Both of them are shown to have feelings for Kanade Amakusa, with Furano wanting Ouka's ability to freely approach Kanade and her ability to say she likes him. They were both jealous when he told Chocolat that he liked her over open microphone but were relieved when he said it was in a platonic way.
One of Ouka's classmates and her friend. Though they get along due to their similar hyperactive attitudes, it is hinted that Ouka is very envious about Kanade and Chocolat being rather close, but remains on good terms with her. It seems the jealously exists on Chocolat's side as well, which was shown after she saw Ouka and Kanade together after he took a picture of her and ran off. She later noted to Ouka that Kanade seemed very kind to Ouka and how she gets uneasy because of it before running off, apologizing for her words as Ouka was shocked.
Ouka was very surprised and worried when she found Kanade and Chocolat hugging as well as when Kanade admitted he liked Chocolat on an open microphone at the park but was relieved it wasn't in a romantic way.
Konagi is Ouka's best friend. Prior to the start of the series, they were both in the same class as freshmen and have stayed by the other's side ever since. It is shown that Ouka's lack of perception and wild behavior, often tends to lead the shy and clumsy Yawakaze to usually being put in some embarrassing situations.
Despite that, both of them have remained good friends even putting aside their social rank differences to associate with one another and have fun.
Also, both girls are shown to have feelings for the same boy but don't seem aware of this fact.
Ouka first met Yuragi when they were introduced to each other through Kanade.
The mother of Ouka. Ouka seems to look up to her to some extent, taking her advice when she says that she should only cry in front of the man she loves.
The father of Ouka. Not much is known about their relationship but Ouka seems to admire him for running a company which allows her to test out its inventions. She seems to be fond of him as she is always happy to bring up that he allowed her to use his experiments for her amusement.