Kazuomi Ōga

Appearance
Kazuomi has light brown hair and brown eyes. While attending Aoba High School, he wears his elder brother's uniform (white shirt, black tie, dark gray full trousers and a light gray full sleeve sweater), which happens to be too loose on him. He has matching piercings with Kariu in his left ear,which was done by his brother. He has received compliments from both, An and Kaizaki on having an attractive physique. Arata has also called Kazuomi good looking multiple times.

Personality
He is very focused on school, and spends most of his time perfecting his grade to get into college. He's seen as being dense in the matters concerning love and relations as he did not know about Kariu's feelings for him.He cares for his friends very much, and often looks up to Kaizaki for advice. He also feels embarrassed after mentioning that he has a girlfriend as a way of boasting to Kaizaki.

History
He has said that his family doesn't have a large amount of money, which is partially why he works so hard to be top of his class. This way his family doesn't have to pay for his meals. He seems to love his brother very much, getting his ears pierced by him.

Relationships
Kaizaki Arata

Ohga shares a warm relationship with Arata. He helped Arata during a routine test on his first day in high school, when Arata had become self-conscious on being caught carrying a pack of cigarettes in his bag(out of habit as an adult). It didn't take long for Arata to nickname Ohga as 'Flashy Dude'; noticing his proactivity in class. Some days later, Ohga noticed how Arata could call An by her first name without honorifics without any hesitation(while he refused to call Ohga as 'Kazu-kun'). This lead him to believe Arata is quite a womanizer and has been through many romantic relationships. His bond with Arata grew stronger as he gave lessons to him and An(as both were poor performers in the routine tests) after school hours. Later during vacations, Ohga had a talk with Arata about his(Ohga) relationship with Rena that prompted him to think about it. He resorted to calling Arata immediately when he noticed Rena with a stranger in a cafe during the vacation(It turned out that the suspicious person helped Rena when she passed out due to sun stroke). After this, he became more self-aware and gradually realized his feelings for Rena. He also confessed to her after a planned outing to watch fireworks with all his close friends.

Kariu Rena

Ohga met Kariu Rena first during his first year in high school. He offered her an ear piercer after getting an ear pierced himself, which Rena accepted and got a piercing done in her left ear. Thereafter, both wore matching ear studs. Both of them earned silver pins as class representatives during the first two years. Ohga earned the silver pin in the third year too, however Rena's position was stolen by Hishiro. Ohga has remained dense throughout the series, which really irritated Rena. During the vacation, Ohga was questioned about his feelings for Rena by Arata, which made him think about it later. Later, while returning from his part-time job, Ohga noticed Rena with some unknown guy in a cafe and immediately called Arata while spying on them.He became tensed when both came out of the cafe and were heading towards a car. Ohga stepped into the scene when Rena accidentally slipped and was caught by the suspicious stranger. He later learnt that the stranger was just a passerby who noticed Rena passing out due to a sun stroke(as she was lingering around Ohga's workplace to steal glances at  him). He realized his feelings when he reflected upon his thoughts and actions that day, for example, when he had an urge to hold hands with Rena as they walked to the station together. Later, after having a talk with his close friends, Ohga planned to confess his feelings to Rena and invited everyone to watch fireworks together. They confessed to each other after the fireworks got over and walked home hand-in-hand.