Like the other members of the F4, Rui is also from a well known, rich and elegant family. He is the heir of his father's company causing him to be strictly supervised. During his childhood, he always have hard time socializing with other people. He is often interpreted as autistic because of his Asperger's Syndrome. He also prefer sleeping 10 hours a day. He became a friend to the other F4 members since their childhood. However, only Shizuka Todo is the only one to make him normal again and start being friendly to others. For Rui, Shizuka is the only girl that attracted him and became his very first love interest. As Shizuka left for her career, Rui's cold behavior was back again.
Hanazawa Rui became a student of Eitoku Academy along with other F4 members. They are known to be the superior students of the school and bully those who refuse to follow them. However, Rui is the only different member. He spends time out of the class just to sit down and relax on their school's staircase which is the most quiet place that can be found inside their campus. He first met Makino Tsukushi
there as she shouts her anger against the F4. Unknowingly, Rui heard it all and was amazed that at least someone especially a girl was able to express her feelings against the F4 despite their superiority in their school. Tsukushi was surprised and thought that Rui is just like his friends, though, he is not. As Tsukushi received her Red Card, she started being bullied by those people commanded by Tsukasa. Rui was the only one to save Tsukushi from them not only for once but for so many times. However, Rui's mysterious behavior started puzzling Tsukushi. Being the number one enemy of Tsukushi, Doumyouji was not her love interest at first. It was Rui who first attracted her because of his difference among the other members.
Tsukushi saw Rui kissing a poster of Shizuka Todo
which she also knops because of the popularity of the aforementioned celebrity. Though, Tsukushi don't really know what their relationship really is. Tsukushi started having conversations with Mimasa and Nishikado about Shizuka and found out about their childhood as they grow up together. Tsukushi then realized the reason why Rui loves Shizuka very much.
Shizuka then arrived and was happy to see the F4 again especially Rui. They conversed and talked about what happened during her absence. Following some events as they started having a party, Shizuka anounced that she is about to leave. Rui became very sad and confessed that his true feelings for Shizuka. However, Shizuka really have to leave for her career. Rui then have no choice but to follow her.
As he arrived, Rui also started having affection for Tsukushi and said that he is starting to love her. Though, it only affected his relation with the F4 and caused troubles to both of them. However, as tsubaki arrived, she was able to solve their problem and bring their friendship back. Rui then learned that Tsukushi and Tsukasa were the really couple.