A first-year high school student. He has no friends and possesses a detached, cynical outlook on life. He is an otaku who loves light novels. While he intended to remain a mere bystander to enjoy a peaceful life, he gets dragged into various troubles after witnessing Anna's heartbreak. He is surprisingly particular about the taste of the school's tap water. He is mentally stable, logical to a fault, and rather blunt. He doesn't speak much.

One of the losing heroines. Kazuhiko's classmate. Because of her good looks, she is popular in class. She has a bright and charming personality but can be a bit airheaded. She is also a massive glutton. She was in love with her childhood friend Sosuke, but Sosuke fell for a transfer student, Karen Himemiya. She ended up supporting him, resulting in her own heartbreak. She considers her relationship with Kazuhiko to be that of "good partners" or "friends."

One of the losing heroines. Kazuhiko's classmate and the ace of the track and field club. With her cheerful personality and athletic looks, she is popular in class. She is not very good at studying. She was in love with her childhood friend Mitsuki, but he only saw her as a friend, leading to her heartbreak. A tanned, energetic girl. She lacks a sense of shame and thinks as long as she's hidden, there's no problem.

One of the losing heroines. Kazuhiko's peer and a member of the Literature Club. Due to extreme shyness, she struggles to communicate with others. She was in love with Shintaro, who had encouraged her, but his heart was set elsewhere. Notably, she is the only losing heroine among them who gathered the courage to actually confess her feelings to her crush.

Karen's boyfriend and Anna's childhood friend. He is handsome, cheerful, and stands out in class. However, he can be tone-deaf to social cues; he once tried to play matchmaker for Anna and Kazuhiko, which only made Anna angry.

Sosuke's girlfriend and Anna's best friend. She is beautiful and well-endowed; Kazuhiko describes her as a "beautiful girl radiating 'Main Heroine' energy." She has a kind heart and cares deeply for Anna. Unbeknownst to others, her relationship with Sosuke is actually quite intense.

Chihaya's boyfriend. He went to the same middle school and cram school as Kazuhiko, though they aren't exactly friends. He has known Lemon since elementary school. He is incredibly dense regarding romance; he didn't realize Lemon liked him—or that she was his own first love—until she finally said something.

Mitsuki's girlfriend. She used to attend the same cram school as Kazuhiko and was famous there for her beauty and excellent grades. While usually gentle, she has a stalker-like and jealous side. she is knowledgeable about electronic devices and minerals.

A third-year student and the president of the Literature Club. He is Koto's childhood friend. He is handsome and tall.

A third-year student and the vice-president of the Literature Club. She is Shintaro's childhood friend. Her test scores are quite poor.