" Tsubaki-kun ! Do you remember me ? Because I remember you !!! Since you asked, you may taste my drool . . . ."
Aika Hayakawa (早川 愛香 Hayakawa Aika) is a girl who was Akira's classmate and first crush in middle school (junior high school). She knew of his deep, intimate feelings for her, but never acknowledged those feelings of love, thus affecting an unrequited love shipping from Tsubaki to her. After middle school, she eventually attended a different high school, an all-girls school, from the one Tsubaki attended.
To everyone else, Hayakawa is a pleasant, popular middle school and high school student, who enjoys life and loves to socialize with friends and have fun. However, Hayakawa, inside, has low self-esteem and little self-confidence in her abilities. Although socially active, and the center of many boy's attention, she actually finds it difficult to form any kind of close and personal relationships. She has been interested in several boys, but all of her efforts to express her love and affection have turned out to be unrequited love. This leads her to often feel lonely and dejected, and will seek out someone she can try to talk to and trust. Since Tsubaki had a crush on her, she also hoped to restart a relationship with him, when Tsubaki told her that he still was still single. Plus Tsubaki told her that he did not have a girlfriend, when in fact he was already in a relationship with Urabe. She is not afraid to let her frustrations out and seek comfort when she is with Tsubaki. However, she has a very possessive personality, and is not below using jealously, deceit, and deception to entice a boy to want to help her and do her bidding.
When Hayakawa's school has the Cultural Festival, she even stoops to faking a bruise to trick Tsubaki to pretend to be her boyfriend for a day, and setting it up so Urabe will come to the school's summer festival during that same day. Hayakawa wanted to separate Tsubaki from Urabe, long enough to, once again, attempt a Drool Bond with him. She also wanted to spite the boy that she had shipped with into shame and regret, not to mention her wanting to be 'ticking off' Urabe. However, at the festival, things do not go as Hayakawa had planned. Hayakawa is then forced to show her true competitive and combative nature, held in reserve until now, when she and Urabe go head-to-head in a battle to gain Tusbaki's attention and admiration, even literally 'baring all' of herself to do so. The outcome leads her to reconsider her relationship with a former unrequited love interest, and after clearing up everything with them, the two begin again with one another on a whole new, deeper intimate level. Hayakawa finally has what she yearned for all this time, a boyfriend and girlfriend socially intimate relationship, founded on a Drool Bond.
Another note about her personality is that she and Tsubaki have similar quirks and behavior, which is why he developed a crush on her to begin with. At the moment, she studies at the Hoshinome Girls' Academy, which is a girls-only high school.
Hayakawa is a petite, attractive teenage girl, originally with long, jet-black hair, but then had it cut short, that Tsubaki has known since they were both in middle ( Jr. High ) school. Hayakawa has always dressed and groomed herself in the 'kawaii' ( super cute ) fashion style, and was very popular in middle school with the boys because of that. She was even able to attain and maintain the near impossible status of concurrently presenting as sweet / innocent, and hardcore sexy, both at school, and out in public. She now attends an all-girl high school, but still maintains her well groomed and professional looking fashion style. She was initially long-haired, but in Anime Episode 10 / Manga Chapter 28 she meets Tsubaki once again, and shows off a new hairstyle wherein she has cut her hair short. However, at Hayakawa's school cultural festival, wherein she meets Tsubaki who is to pretend to be her boyfriend, she wears an exact duplicate of her middle school jumper dress school uniform, and has a long, black wig, so that she looks exactly as she did a few years ago. Finally, it is shown that Hayakawa has an almost perfect 'teenage fashion model' body size and shape, when Tsubaki sees her unclothed, as part of a very combative challenge game of 'Do or Die' that she participates in during the Hoshinome Cultural Festival.