Suguru is (spoiler: until he leaves Hanadera!!!) the student council president at Hanadera Academy. He is also both Sachiko's cousin and her betrothed through an arranged marriage. Although he's seen as being a bit on the arrogant and self-absorbed side, he's actually quite easy-going. He cares about his cousin, but doesn't seem all that interested in marrying her.
Suguru was betrothed to Sachiko as a child and although Sachiko harboured romantic feelings towards him, Suguru was not romantically interested in her due to his sexuality. When Sachiko started high school, Suguru told her that he was a homosexual so if she wanted children she would have to take a lover outside of their marriage. The reason for their engagement mainly stemmed from the fact that Sachiko was the only child of the Ogasawara family. Her grandfather prefered to have a male take charge of the company but also wanted the heir to be part of the family. Suguru seemed to be the logical choice but Instead of just adopting Suguru into the Ogasawara family, Sachiko's grandfather engaged him to Sachiko. This way Sachiko would also be at the head of the family when the time came for Suguru to take over.
He is Sachiko's cousin and arranged fiancé, because in order that a trusted man inherit the company owned by the Ogasawaras, their engagement was arranged, although Sachiko detests it and denies that he is her fiancé. He is very arrogant, and especially disliked by Sei, but he has prestige in Hanadera Boys' Academy since he is president of the Student Council there when the story begins. He is gay, and appears to have a crush on Yumi's brother, Yūki. Despite his arrogance (and a fast car), he does somewhat cares about Sachiko and is glad she has Yumi as a good friend. He also serves as a representative for the Matsudairas, keeping a close eye on Tōko. He also shows that he deeply cares for Tōko, displayed in the fourth season when, enraged by her bullies at their summer home, he put his car in Race Mode (he pushed the pedal fully down to the metal) as the traffic lights went green. He has a reputation for his horrible driving skills—many people have given this feedback after taking a ride in his car (such as Sachiko, the Fukuzawa siblings, and Yoko).
Surugu is the cousin and fiancée of Sachiko and also the cousin of Touko. He is quite protective of both of them. Suguru enjoys toying aroung with Yumi's brother Yuki and nominates Yuki for student council president shortly before graduating. In the later books/ seasons we come to realize that Surugu cares deeply for Yumi although she views him as a rival for Sachiko.
- "He… Suguru-san, is not a bad person. But he acts only for himself, but he doesn't seem to realize it. He can't understand how other people feel, nor does he bother to even think about it. That's why if he hurts someone, he doesn't understand why, and he doesn't even think about whether he was the cause." ~ Sachiko (Light Novels Vol. 1)
- "Kashiwagi-san, that idiot, was talking with the college-aged Onee-sans around him, and his speech seemed to make the surrounding flowers bloom." ~ Yumi's P.O.V. (Light Novels Vol. 21)
- "Then why did you tell Sachko-sama that?"
"That you're gay."
When Yumi said those words, Kashiwagi-san's normally self-confident, youthful figure faltered for just a moment.
"... My god. Just how much do you know."
- "There's some parts of me that even you can't see." ~ Suguru [To Yumi] (Light Novels Vol. 21)