Ninako is the protagonist of the story who comes off as a clueless Naïve Everygirl, but only truly understands things if she tries it herself. She falls in love with Ren and struggles with her newfound feelings for him.
- Beautiful Dreamer: Ninako falls asleep on Ren's shoulder on the train one afternoon. Ren stays with her until her stop instead of getting off at his.
- Boy Meets Girl: Boy Meets Girl On Train (for Ninako/Ren). Boy Meets Girl But Girl Was Expecting Other Boy (for Ninako/Ando).
- Curtains Match the Window
- Naïve Everygirl: The manga explores Ninako dealing with her first experiences.
- Single Girl Seeks Most Popular Guy: She falls in love with Ren, the most popular boy in her school.
Ren Ichinose is the most popular guy in school. He seems cold at first glance, but is actually a nice guy and somewhat shy.
- Always Save the Girl
- Beautiful Dreamer: Ninako catches Ren sleeping before a student council meeting and means to wake him up, but she feels bad for disturbing him and lets him sleep. She ends up falling asleep too.
- Big Man on Campus
- Boy Meets Girl: Boy Meets Girl On Train (for Ninako/Ren).
- Curtains Match the Window
- Defrosting Ice King
- The First Cut Is the Deepest: After Mayuka and Ren break up, it takes about four volumes for Ren to move on, and he only does so after he sees Yuu bring a conclusion to his relationship with Sayuri.
- Friendless Background: In middle school, Ren didn't have any friends and was ostracized by the boys for being popular with the girls... and his only best friend lost trust in him after an incident that wasn't even his fault.
- Green-Eyed Monster: Ren briefly gets jealous of Toda when he notices that he and Ninako get along with each other really well, to the point where Ninako chose to confide in him about her problems rather than Ren himself.
- Hard Work Hardly Works: When Ren realizes he and Mayuka are beginning to get distant, he does all he can to prioritize her needs. They break up anyway.
- Nice Guy: Even though he looks intimidating, he's really a nice person, and it's because of this Ninako befriends and falls in love with him.
- School Idol: He's the most popular boy in school. An article for the live-action film adaptation even describes the character Ren as a "cool campus idol."
- Second Love: He later reciprocates Ninako's feelings for him.
- Tall, Dark, and Handsome: He's tall, has dark hair, and has looks that are very popular with the female population at school.
- The Rival: Ando.
- Unwanted Harem: Ren doesn't really understand why he's popular, but he still keeps the love letters anyway.
- When He Smiles: Ren rarely smiles, but when he does, it captivates everyone. The reason why he doesn't smile very often is because Ando told him that he looked horrible smiling, causing himself to nickname his smile the "death smile."
Ren's middle school friend. Ando develops unrequited feelings for Ninako.
- Always Someone Better: Ando is frustrated that Ren is always ahead of him when it comes to Ninako. Most of his anger comes from when they used to be best friends in middle school until he lost his First Love to him.
- Boy Meets Girl: Boy Meets Girl But Girl Was Expecting Other Boy (for Ninako/Ando).
- Brutal Honesty: Ando openly confesses to Ninako and also directly confronts her feelings when he knows she is pretending to be strong in front of Ren.
- The Casanova: Ando enjoys flirting with girls and his phone number is full of their phone numbers, but none of the relationships are serious. It's also implied that he has sex with them often, too.
- Curtains Match the Window: Golden hair + Gold eyes.
- Dogged Nice Guy
- Green-Eyed Monster: Ando is jealous of Ren, who was kissed by his first love during middle school and is now the object of his second love Ninako's affections.
- Handsome Lech
- Hopeless Suitor
- Jerk with a Heart of Gold
- I Want My Beloved to Be Happy
- Ladykiller in Love: Ando stops his Handsome Lech tendencies when he decides to pursue Ninako, but falls short into this after he gets beat up minutes before Ren's Love Confession to Ninako.
- Second Love: Ninako is the first person Ando falls in love with following his break-up with his former girlfriend.
- The Rival: Ando sees Ren as a rival for Ninako's attention.
- Troubled, but Cute
Ninako's childhood friend. Daiki has feelings for her.
- Anguished Declaration of Love: Daiki confesses to Ninako even though he knows she likes Ren.
- Clingy Jealous Boy: A mild degree when Daiki realizes Ninako feels "something" towards Ren and sees Ren as his love rival for Ninako's affections.
- Curtains Match the Window
- Demoted to Extra: Once Daiki gets over Ninako, he only appears sporadically for the rest of the manga. He does get involved in the main plot every now and then, but only as a side character.
- Dogged Nice Guy
- Hopeless Suitor: Towards Ninako.
- Large Ham: Daiki tends to act showy and childish, but Sayuri likes it.
- Pair the Spares: Ends up dating Sayuri, Ninako's friend.
- The Rival: Daiki sees Ren as this at first.
- Second Love: Sayuri confesses to him shortly after he gets rejected by Ninako, and they end up dating for real around volume 3.
- Unlucky Childhood Friend: Suffice to say, he never wins Ninako's heart.
- Ascended Extra: Sayuri gains more plot significance once the manga begins to deal with her relationship with Daiki. Also, out of Ninako's friends, she is the only one featured on the cover of one of the manga volumes.
- The First Cut Is the Deepest: Sayuri begins to avoid Daiki when she thinks he cheated on her on the school trip. She's afraid of talking to him honestly about this because when she was in middle school, her boyfriend, who happened to be Yuu, was stolen by a girl.
- Second Love: For Daiki, she is his second love. In regards to herself, Yuutarou may have been her second love, but it's unclear to how many boys she dated before him.
TsukasaTsukasa is another one of Ninako's friends and was Manabu's classmate in middle school.
Tamaki and Noriko
- Ascended Extra: He was originally part of Those Two Guys with Yuu, but gets a larger role after volume 3.
- Keet: He's the most cheerful out of Ren's friends.
- Only Known by Their Nickname: Due to Alternate Character Reading, "Manabu" can also be read as "Gaku", therefore he's known as "Gacchan" to the girls. In the English publication by Viz Media, this is not so prevalent, as Viz's translations did away with most of the nicknames and Last-Name Basis.
- Shipper on Deck: Manabu ships Ren and Ninako and has on more than one occasion tried to get them together. It gets to the point where Yuutarou has to call him out and tell him to mind his own business.
- Stepford Smiler: Manabu shows a minor case of type A at the end of his side story after Ritsuko, his First Love, goes to study abroad.
- Ascended Extra: He was originally part of Those Two Guys with Manabu, but gets a larger role after volume 3.
- Big Brother Mentor: He assumes this role when he sees Ren fumble over his newfound feelings for Ninako.
- Characterization Marches On: Before becoming an Ascended Extra and receiving Character Development, Yuu had a carefree personality. This was also partially due to Early Installment Weirdness.
- I Want My Beloved to Be Happy: He dated Sayuri when they were in middle school. When Sayuri starts believing Daiki could be cheating on her, rather than taking advantage of the rift between their relationship, he encourages her to make up with him.
- Only Known by Their Nickname: Everyone either shortens his name to "Yuu" or Tera."
- Wise Beyond Their Years: Yuu is extremely wise and often gives advice to both Manabu and Ren.
Mayuka is a famous model, Daiki's older sister, and Ren's girlfriend.
- Cool Big Sis: Mayuka is Daiki's older sister and comes off as very gentle and friendly.
- I Want My Beloved to Be Happy: She breaks up with Ren because she knows she is holding him back from accepting his feelings for Ninako.
- Please Don't Leave Me: Mayuka is constantly afraid that one day Ren will leave her. She's the one who ultimately leaves him.
- Role Reprisal: Yui Shouji is the only voice actress to return for the drama CD adaptation while everyone else was replaced.
- Romantic False Lead: She's a more likable and sympathetic kind of False Lead than usual.
- Sibling Yin-Yang: Mayuka's the Foolish Sibling to Daiki's Responsible Sibling. She's peppy and cheerful in comparison to Daiki's more cynical behavior (when he's not being a Large Ham, of course) and has more of a harder time accepting her parents' divorce while Daiki has pretty much come to terms with it.
Mao is Ando's First Love and ex-girlfriend one year his junior who cheated on him with Ren, permanently damaging their friendship.
- The Atoner: Mao wants to help Ando and regrets hurting him in middle school.
- Becoming the Mask: Mao originally dated Ando just to get over Ren, and ended up falling in love with him for real.
- Bitch in Sheep's Clothing: Mao acts as a Manipulative Bitch to separate Ninako from Ren, but turns out to be a Red Herring because she is doing it to get Ando and Ninako together.
- I Want My Beloved to Be Happy: Mao interferes with Ninako and Ren's relationship only because she knows Ando likes Ninako.
- Must Make Amends: Mao wants to make up for hurting Ando.
- Your Cheating Heart: In middle school, Mao accepts Ando's Love Confession only after hearing that Ren, who she liked, already had a girlfriend. While she did come to like Ando, she became unsure of how she felt after talking to Ren, culminating in her giving him a kiss. That incident has become a source of friction between Ando and herself, as well as permanently damaging Ando and Ren's friendship.
Keisuke TodaKeisuke Toda is an upperclassmen who becomes the leader of cheer squad for Ninako's team for the sports festival.
- The Confidant: Ninako chooses to confide in Toda about her problems since they directly involve Ren and her friends. Toda continues to give advice and his perspective on the matter as an outsider.
- Large Ham: He yells and strikes a lot of extravagant poses, to everyone else's dismay.
- No Indoor Voice: Subverted. He normally yells in a loud voice, but in chapter 29, he speaks to Ninako softly and Ninako even Lampshades it in her thoughts.
- Tragic Dropout: Toda tells Ninako that he's dropping out of school after the sports festival so that he could find a job to support his family.