Though Taichi doesn't speak much, he's very sympathetic towards others and wants to help his friends when they're having trouble. He tends to become very passionate and gets carried away whenever he starts talking about his hobby, pro-wrestling, and Inaba stops him when he tries to add wrestling topics to their Student Cultural Society's newspaper. He has a little sister in elementary school, Rina.
- 10-Minute Retirement: Temporarily stops helping his friends after an argument with Aoki that ended with him accidentally hurting Iori.
- Apologizes a Lot: Part of his Nice Guy shtick. He's always the first to apologize when something goes wrong.
- Big Word Shout/Say My Name: In episode 5: NAGASE!
- Cannot Spit It Out: Taichi seems to have a lot of trouble expressing his feelings to girls.
- Chivalrous Pervert
- Chronic Hero Syndrome: Oh, SO MUCH.
- Deconstruction: In every arc, his repeated attempts at being selfless end up either straining his friendships, or causes more harm down the road.
- Eventually, by the time of Heartseed's 6th phenomenon, his underlying Martyr Without a Cause problem is brought to light, and the arc highlights how Taichi lacked a mind of his own, that he merely blindly responded to the wishes of others and never stop to think about his own perspective, approach or responsibility to the situation, or whether it was in the best interest of the others. In both Inaba and Fujishima's words: He is like a mindless, RPG game avatar. This eventually led to him causing trouble in the school and injury for his classmates, as well as Inaba breaking up with him, who was deeply pained by his seemingly lack of concern regarding their relationship. It was a harsh lesson for him.
- Deconstruction: In every arc, his repeated attempts at being selfless end up either straining his friendships, or causes more harm down the road.
- Dark Secret: His deep, dark, dramatic secret to Inaba is... he's thought about her (as well as Iori and Yui) while dating Rosie.
- Double Standard: Abuse, Female on Male: Courtesy of Inaba.
- Epiphany Therapy: Taichi acts as therapist to everyone during the Hito Random arc, but he only manages to put them on the track towards overcoming their problems.
- Fan Boy: Of Professional Wrestling. His friends hardly share his passion.
- First Kiss: Is Iori's first... and at the same time, Inaba's... It's a Long Story...
- The Heart: According to Iori.
- Heroic Sacrifice: Taichi seems to desperately want to pull one off any chance he can.
- The Idealist: His advice to others is always filled with overwhelming idealism and optimism, though maybe that's just what they need to hear at the time.
- In-Series Nickname: "Selfless Freak."
- It's All About Me: Revealed that his constant need to help people is his own way of dealing with his own pains, so in a way it is selfish.
- Inverted later in that he doesn't really think for himself. See Deconstruction above.
- Jobber: Taichi respects Professional Wrestling jobbers because of the way they endure pain and lose for the sake of bolstering a fellow wrestler. This philosophy reflects Taichi's own character.
- Knight in Shining Armor: How others start to see him, but Taichi is not without his flaws.
- Laser-Guided Amnesia: He loses his memories of the Cultural Club and everyone in it due to the Forced Termination phenomenon in Nise Random. He manages to recover thanks to Chihiro and Shino's efforts.
- Loss of Identity: By Yume Random it is full blown. Taichi has become so wrapped up in playing the hero he has completely lost sight of himself.
- Love Confession: Gives one to Iori and receives one from Inaba
- Gives a long, thoughtful one to Inaba to earn her back after their Second Act Break Up.
- Man, I Feel Like a Woman: The first time Taichi switches bodies with Iori, his first action is naturally to grope himself.
- My God, What Have I Done?: Due to his personality, he has done quite a number of things that he regrets right away throughout the series. Such actions include hurting Iori and allowing his selfless obsessions to get between him and Inaba.
- My Sister Is Off-Limits!: Taichi tends to get quite anxious anytime his Rina is the focus of anyone's attention.
- Nice Guy: Aside from his Chronic Hero Syndrome tendencies, Taichi is a very sweet guy at his core.
- Not So Different: In the 6th arc, Heartseed claims the two of them are quite similar. Inaba points it out to Taichi once more later.
- Not What It Looks Like: A magnet for these kinds of situations. Typically leads to a She Is Not My Girl Friend moment.
- Official Couple: Goes out with Inaba at the end of Michi Random.
- Oh, Crap!: Almost constantly throughout Episode 5.
- "The Reason You Suck" Speech: Gives Inaba one after his impulses are unleashed in Episode 7, though he regrets it.
- Has a full on Reason You Suck war with Aoki in Episode 8.
- Second Love: With Inaba, after concluding his relationship with Iori at the end of the anime
- Secret Keeper: Is such to many of the characters who Taichi acts as therapist to. Also keeps the existence of No.2 a secret under threat.
- She Is Not My Girlfriend: At one point or another denies being so to Iori and Yui.
- Ship Tease: Definitely with Iori.
- And a lot of it with Inaba.
- Plus some non-comedic examples with Yui.
- And with... Aoki
- Taking the Bullet: Takes a lead pipe to the head while protecting Inaba from a thug. He recovers.
- Tempting Fate: When Iori first open up her identity problem to him, he promised that "No matter what happens, no matter what you've become, I will know that Nagase is Nagase." Well... guess what happens next episode...
- Triang Relations: Type 4 with Iori and Inaba at the end of Kizu Random arc.
- The Unsmile: According to Yui and Aoki. In fact, of all the main characters, Taichi seems to show his pearly whites the least.
- What the Hell, Hero?: In episode 8, when Iori tries to get between him and Aoki to calm both of them down from their heated argument, his impulse "unleashed" and he violently shoved her aside towards a locker, injuring her. Taichi is left horrified by his actions, but what he's most ashamed of is that his desire being unleashed proves a part of him really did mean it.
Iori is Taichi's classmate, a bright, friendly, popular girl. She's the president of the Student Cultural Society, but rather than lead everyone, she sets the mood and gets them excited. Occasionally she takes bold actions in front of others, be it due to carelessness or simple naivety.
She had 5 different fathers in the past. And as her first stepfather turned out to have violent tendencies, she had learned to alter her personality to appease and fit the expectations of others to the point where she had become unsure who she was originally supposed to be.
- Abusive Parents: Her first stepfather turned out to be like this and he became the reason why Iori started taking on multiple personalities.
- Achilles in His Tent: her persona-changing proves instrumental in saving Inaba from the Hostage Situation
- Amicable Exes: With Taichi.
- Beauty Mark: Below her mouth.
- Became Their Own Anti Thesis: In Michi Random when Iori decides to finally "solve" her Loss of Identity.
- Beneath the Mask: As revealed in Michi Random, her true self is moody, critical and angry. It is later revealed that this was just another extreme persona Iori conjured up, hoping it was her true self. Eventually, Iori decides to just stop caring and act however she likes. The true Iori is something in between the extremes, bubbly and loving, but also firm when she needs to be.
- Berserk Button: Don't harm her friends. Just... don't.
- Break Them by Talking: Hurls a barrage of Armor Piercing Questions at Inaba and Yui both in Michi Random, leaving both speechless.
- Broken Bird: A traumatic childhood has seeded self-loathing and bitterness in Iori.
- Cuddle Bug: She isn't afraid to get touchy-feely with others.
- Everything but the Guy: Iori ultimately decides against dating Taichi. By the end of the series, she remains single, but has grown significantly as a person, rescued her mother from a terrible decision, amassed a group of loving friends, and conquered her Loss of Identity. She does admit she wouldn't mind getting a boyfriend eventually though...
- Expository Hairstyle Change: After the events of Michi Random, she no longer wears a pigtail and grows her hair long
- Face Death with Dignity: When told of her impending death in Hito Random, Iori is brave and chooses to spend her last moments speaking to her friends. However...
- First Kiss: Was taken by Taichi... in Inaba's body
- The Gadfly: She's not really as goofy as she seems, most of it is just an act to push some buttons or rustle up some laughs.
- Genki Girl: Fun-loving, expressive and a bursting with energy. Taichi considers Iori the source of the StuCS's spirit.
- I Want My Beloved to Be Happy: Zig-zagged. She wants Inaba to win Taichi, but also won't give him up without a fight.
- Large Ham: Bursting in through doors and shouting randomly is general business for Iori.
- The Leader: Develops into a Type IV, the core and heart of the Cultural Club. Initially, however, Iori is overshadowed as leader by the more assertive Inaba.
- Leaning on the Fourth Wall: In the Michi Random arc, she asks why everyone treats her like a "tragic heroine who needs saving."
- Let's Fight Like Gentlemen: Non-violent example with Inaba over Taichi.
- Loss of Identity: She suffers from this ever since she started assuming different personas for different situations.
- Modesty Shorts: Never leaves home with 'em.
- The Nicknamer: She coins several names such as "Inaban" and "Dereban" for Inaba, and later "Chihhi" for Chihiro.
- Notable Non Sequitur: Any conversation she has with Taichi tends to have a cryptic hint of something that's to come sprinkled in.
- Perpetual Smiler: She seems to be this, but is actually...
- The Pollyanna: The personality she actively tries to cultivate, but she's proven to have her limits.
- The Power of Acting: A skill acquired from years of faking personas. It was enough to keep her violent stepfather at bay, and fool Taichi, too.
- Rage Breaking Point: She finally snaps in Michi Random.
- "The Reason You Suck" Speech: Gives one to Inaba at the end of episode 15. It was brutal.
- Sad Clown: Spontaneous and foolhardy, but it's all just a forced act. The true Iori is an insecure and lost soul.
- Shipper on Deck: After Michi Random she full-time ships Taichi and Inaba.
- Ship Tease: With Taichi, courtesy of Inaba.
- The Social Expert: A factor of her persona changing. Iori has become accustomed to reading and anticipating the social cues of others, allowing her to predict their motives and true feelings, which she can then adapt to.
- Split Personality: Not a case of actual different personalities, but more on the lines of her wearing multiple masks, while not having a mirror to see her own face.
- The Tease: She loves making perverted jokes around Taichi.
- You Gotta Have Blue Hair: Although the actual color is rather inconsistent, shifting between purple and dark blue.
Himeko is vice president of the Student Cultural Society. She excels in gathering information and analysis, possessing private data on each of the club members. She's calm and logical, but she's also rather blunt, so she has difficulty dealing with delicate situations.
Due to certain reasons she prefers everyone else, with the exception of her family, to addressed her by last name, Inaba.
She had an inherent difficulty in trusting anyone including herself. However, as she had pointed out herself, unlike her friends she did not experience any particular trauma; she was born with such personality. She deeply despises herself for this, which results in her rather negative self-esteem.
- Anger Born of Worry: She frequently criticizes and lectures her friends, but only because she cares.
- Beneath the Mask: Behind her high and mighty front is a self-critical, lonely girl with abysmal self-esteem.
- Black and White Insanity: Early on Inaba considers her friends "good" and herself entirely "bad." She manages to overcome this with Iori's help.
- Call-Back: Tries to use Taichi's Dark Secret strategy on Iori. Unfortunately, it doesn't work as Iori was not interested in her embarrassing secret at the time.
- Clingy Jealous Girl: After Iori innocently hugs Taichi and calls him "onii-chan" (big brother), Inaba looks visibly irked. As Iori continues to innocently say things, Inaba continues to get a bit angry at him for apparently enjoying it. She is full-blown once she starts dating Taichi.
- Consummate Liar: She can lie completely straight faced. Iori thinks Inaba has a future as a con artist.
- Corporal Punishment: She seems to regularly administer forehead flicks when a club member steps out of line.
- Covert Pervert: Surprisingly she can be quite perverted, every volume she says at least one sex-related phrase or topic (Which are of course all directed towards Taichi). The fact that she is dead serious about what she says sometimes, doesn't help.Inaba: "Ah... Is that so... Taichi thinks I smell good... Then again I'd really want a chance to blend our scent together soon." *giggles*
- The Cynic: Starts out as one, but by the Kako Random arc, she becomes noticeably more idealistic.
- A Date with Rosie Palms: Confesses to have done so while thinking of Taichi, once to Taichi himself and once to Iori.
- Damsel in Distress: She is kidnapped by some delinquents near the end of Michi Random.
- Defrosting Ice Queen: Towards the rest of the StuCS, but especially towards Taichi.
- Genre Savvy: Catches onto how Heartseed thinks fairly quickly.
- First Kiss: Was technically taken by Taichi twice. The first time was actually Nagase kissing Taichi in Inaba's body, the second time was of Inaba's own free will after her Love Confession.
- Foil: To Iori. Inaba being the cool, commanding and blunt member to contrast Iori's bubbly, happy-go-lucky and sweet character. The contrast takes on a new meaning when it is revealed both have their own deep-rooted insecurities, and their respective personalities were fabricated to help them cope.
- Freudian Excuse: Notably Averted. Inaba actually doesn't know what caused her to become so untrusting and cold. She thinks she was just born that way.
- Friendless Background: Before joining the Cultural Club.
- Hates Being Alone: Despite—or perhaps because of—her cold nature. So much so that she was willing to sacrifice her love for Taichi if it meant getting to keep her friends.
- I Just Want to Have Friends: Type B.
- Heroic Self-Deprecation: Despite acting superior and cocksure all the time, Inaba actually has some serious self-esteem issues and thinks of herself as pathetic and weak.
- Hypercompetent Sidekick: To Iori. It's to the point where people tend to believe Inaba is the club's president, not Iori.
- I Just Want My Beloved to Be Happy: Initially wants Iori to date Taichi so both will be happy, but, with Iori's own encouragement, she decides to act on her feelings for Taichi anyways.
- Insecure Love Interest: Once she and Taichi start dating, she tends to ask him whether he made the right choice between her and Iori; he insists that he did, though she remains insecure.
- Last-Name Basis: Her friends only refer to her as Inaba. As revealed in the novel, this is because she dislikes the idea of being called "princess (Hime)" that is constantly in need of protection by others, which reminds her of her weak, true self.
- The Leader: Type II, being level-headed and quick-thinking.
- Limited Social Circle: Her social circle does not extend past the Student Cultural Society. Inaba later socializes more, but no relationships are ever as deep as the ones she forms in the club.
- Lonely Rich Kid: Well-off family? Check. Crippling chronic loneliness. Check. While it's never outright stated that the two facts are related, the connection between them is utilized to great effect: Inaba's bedroom is positively massive, but almost entirely empty, and almost entirely dark, other than the corner with the computer in it where she's implied to spend most of her free time. The solitude and misery are almost tangible.
- Love Confession: To Taichi in episode 10.
- The Matchmaker: She's a Shipper on Deck for Taichi x Iori. ... and things get complicated when Inaba realizes that she likes Taichi, too.
- Manipulative Bastard: Her impressive lying skills coupled with her intimate knowledge of other people's secrets gives her the impression of one.
- Ms. Fanservice: Ooooh yeaaaah. If someone's gonna wind up in their underwear, chances are, it's gonna be Inaba.
- Non-Action Snarker: Plenty of snark to go around, but Inaba has repeatedly been shown to be the least athletic of her friends.
- Official Couple: Goes out with Taichi at the end of anime.
- On the Rebound: Invoked and Downplayed; after she and Taichi become a couple after Valentine's Day. Taichi had actually asked out Nagase first and got rejected, though Taichi admits to Inaba that had he talked to her first, he would have waffled on his confession.
- "The Reason You Suck" Speech: Who has she not given one to?
- Towards Taichi for his "selfless freak" personality in episode 5.
- Delivers a rather nasty one towards Yui during her "unleash" in episode 7.
- Delivers yet another one towards Iori in episode 16.
- And finally, delivers her best ones towards Taichi, again, in Yume Random arc.
- Sacred First Kiss: She does not take it well when she hears from Iori that the latter shared her first kiss with Taichi in the former's body. To fuel the Ship Tease, technically both girls had shared their First Kiss with Taichi.
- Second-Act Breakup: With Taichi, in Yume Random arc.
- Shipper on Deck: For Taichi and Iori. Until Iori finds out about her crush and calls her out in it.
- Ship Tease: With Taichi.
- Sickeningly Sweethearts: Inaba towards Taichi, especially during the early stages of their relationship, but she mellows out later.
- The Snark Knight: Inaba has a habit of pointing out the flaws of others, but the person she's the hardest on is herself.
- Sugar-and-Ice Personality: Inaba can come off as harsh and distant, but she seems to truly adore her friends deep down.
- Team Mom: Inaba takes it upon herself to understand and counsel her friends.
- Tempting Fate: While making their way to Iori's house, Aoki suggests it would be quicker to take a bus but Inaba states they can't risk anyone seeing them if one of them randomly reverts to a child. Seconds later, Aoki reverts to a child.
- What Beautiful Eyes!: In the novels, Taichi is frequently captivated by her eyes.
- What the Hell, Hero?: Iori finally berates her for insisting that she pursues Taichi romantically, all while Inaba herself confessed to Taichi and Iori is going through an emotional crisis. Way to go...
- When She Smiles: Of course, Inaba smiling is not always a good thing.
- Wrestler in All of Us: After Gotou announces he would remain advisor for both the CRC and Jazz Club, despite the main characters busting their butts to win the competition, Inaba puts him in a Kimura Lock.
- You Are Better Than You Think You Are: Receives one from Iori in episode 10.
Yui is very active and expressive. She's a bit small, but she holds ranks in Karate, and even won tournaments when she was in middle school. She absolutely loves cute things, and her room at home is filled with fancy items. She always ends up insulting Aoki when he tries to approach her.
It was revealed that Yui was a victim of attempted rape in middle school, which resulted in her androphobia.
- Action Girl: An accomplished martial artist. Puts her Karate skills to good use when she, Taichi, and Aoki rescue Inaba in Episode 17.
- A-Cup Angst: Doubles as her Berserk Button.
- Anchored Ship: Type 3 with Aoki.
- Cuteness Proximity: Yui loves plush dolls, but pretty much anything cute turns her to goop.
- The Cutie: The others outright admit they tease Yui just to see her cute reactions.
- Cute Bruiser: Cute as a button, but she can lay you out if she has to!
- Does Not Like Men: She was almost raped in middle school and, as a result, developed androphobia. She tries her best to hide it so as to not put off her friends.
- Face Your Fears: A major theme of Yui's character is learning to confront her insecurities and phobias rather than letting herself be victimized.
- Girls Love Stuffed Animals: Her room is full of them.
- Groin Attack: Taichi kicks her there during a body switch while teaching her how to Attack Its Weak Point.
- Hair Decorations: Her little hair clips.
- Heroic BSoD: Gets a nasty one for most of Kizu Random.
- Laser-Guided Amnesia: She loses her memories of the Cultural Club and everyone in it due to the Forced Termination phenomenon in Nise Random. She manages to recover thanks to Chihiro and Shino's efforts.
- The Not-Love Interest: Invoked multiple times with Taichi who Yui has a soft-spot for since he was the first person she was able to open up to regarding her past trauma. This causes some minor drama with both their respective actual love interests, with Yui having to reiterate that she isn't actually romantically interested in Taichi despite how much she respects him.
- Official Couple: With Aoki by the end of Yume Random.
- Older Than She Looks: Her friends have to remind themselves that she's actually the same age as them.
- Rape as Backstory: Her androphobia stems from an attempted rape.
- Tsundere: Type B; the only person who gets the tsun is Aoki.
- Waif-Fu: Has a black belt in Karate, believe it or not and can easily knock out boys twice her size.
- Weight Woe: Generally speaking, Yui does not like any attention to be on her figure, ever.
- Wide-Eyed Idealist: Having never been in a relationship before, Yui's idea of romance is shown to be quite... romanticized.
- The Worf Effect: Is tossed aside by Heartseed in their first encounter.
- Worthy Opponent: To Mihashi
Yoshifumi is Yui's classmate. He holds affection for her, and continues his attempts to approach her, but she never gives him a chance. In the Cultural Research Club he's often called out, and his pathetic side stands out more, but he also relaxes them with some of his casual statements.
- Abhorrent Admirer: For Yui. It's later subverted, since she doesn't dislike the idea of them becoming a couple, but her androphobia makes it very hard for her to accept his feelings.
- Anchored Ship: With Yui, but he's making progress.
- Book Dumb: Living as carefree as Aoki is a double edge sword — he's rarely takes studying seriously.
- Bromantic Foil: To Taichi, being the goofy, pervert to contrast Taichi's mature personality.
- Butt-Monkey: His friends rarely take him seriously, and always seem to look down on him even when they compliment him.
- Chivalrous Pervert: Is willing to help his beloved Yui... by inviting her to a love hotel.
- Comically Missing the Point: Inaba confesses that she doesn't trust her friends and Aoki gets excited because she's paranoid of everyone, not just him.
- Double Standard: Abuse, Female on Male: Is practically the Chew Toy along with Taichi, but Aoki receives far more of this than the latter.
- Dumb Is Good: Aoki is simultaneously the nicest member of the Student Cultural Society, and the dumbest.
- Hypocritical Humor: "Trust is important these days, right? I would never abuse someone else's body!" The very next episode he's posing for cute pictures with Yui's body. He gets caught.
- Last-Name Basis: Strangely, no one ever calls Aoki by his given name.
- Averted once or twice in the dub; Taichi addresses Aoki by his first name.
- Love Confession: Has apparently given many to Yui, and has apparently been rejected each time. However the latest one has shown that he still has a chance.
- Master of None: Not prone to breaking down as seriously as his friends, but lacks the capability to help others as much as he'd like.
- My Friends... and Zoidberg: Gets this from Yui and Inaba a lot.
- Official Couple: With Yui by the end of Yume Random.
- Over Shadowed By Awesome: Feels this way towards Taichi early on.
- Plucky Comic Relief: A Deconstruction of one. Jokes and silly antics are all Aoki has going for him, so he deliberately acts the fool to lighten the mood. Should he ever fail at this role, Aoki will become depressed since that would make him completely useless.
- "The Reason You Suck" Speech: Trades speeches with Taichi in episode 8.
- Sliding Scale of Silliness vs. Seriousness: Tends to stay in the silly range, but he has his moments.
- Static Character: Deliberate on Aoki's part. Despite Heartseed calling him useless to the others, Aoki insists that continuing to be himself is the best thing he can do for them.
Fujishima is Class 1-3's representative and as such, is a classmate of Taichi, Inaba, and Iori — the latter of whom she is madly in love with. After learning of Taichi's feelings for Iori, she becomes a sort of love rival to him.
- Bi the Way: She claims to go both ways.
- Break the Haughty: Downplayed, but Fujishima does not take it well when Setouchi is chosen as class representative instead of her during their second year. This becomes a turning point in Fujishima's character where she becomes more humble and her Large Ham qualities are mellowed.
- Friendly Enemy: To Taichi at first, but gradually turns into a straight, albeit awkward, friendship.
- The Heart: Throughout the series, whenever the heroes are in a rough patch they can't seem to resolve, she comes out to dispense advice or otherwise lend a hand. She does this for everyone in her class, as just after giving Taichi advice in episode 8, she answers a call from someone else about love problems.
- Hero of Another Story: The only supporting character who has a full length side story dedicated to her in the novel.
- Love Freak: Fujishima takes it upon herself to make sure her fellow students are in good relations with each other whether they like it or not. She also loves to play matchmaker.
- The Matchmaker: She tries to set up Yui with Misaki and Taichi with Inaba, if just to get Taichi out of the way so she can have Iori to herself.
- The Rival: Fujishima declares herself as such to Taichi. Doesn't stop her from helping him whenever he needs it.
- Scary Shiny Glasses: She does this a lot.
- School Girl Lesbian: Played for laughs with Iori, who is terrified of her.
- Single-Target Sexuality: Iori, again.
- Team Mom: Thinks herself as this for her class.
Homeroom teacher of our unlucky group. Also serves as a host for Heartseed, who occasionally takes control of Gotou's body to explain something to our protagonists. Gotou in his place have no recollection of what happenes at those times. When he isn't spending his time possessed he is a very laid back and friendly teacher; gets by with having his students do his work for him. When he's actually serious he can give out surprisingly good advice, and seem like an actual teacher. However, any time when our protagonists are about to appreciate his wisdom, he reverts back to his usual goofiness (much to their chagrin.)
- Butt-Monkey: Out of all his students, only Taichi gives him a shred of respect.
- Hidden Depths: He's a brilliant saxophonist.
- Hippie Teacher: Very laid-back and does not mind being called Mr. Go by his students.
- Lazy Bum: Inaba outright calls him out on this, but he has his brilliant moments, too.
- Locked Out of the Loop: Though it's probably a good idea to not let Gotou know that a supernatural being frequently high-jacks his body and there's nothing he can do about it.
- Mind-Control Eyes: Anytime Heartseed possesses him, Gotou's eyes will dull out.
- Psychologist Teacher: To Taichi in episode 8.
- Weirdness Censor: The reason Heartseed keeps using him as a vessel is because most other people would be concerned at missing significant chunks of time.
A student of class 1-C and one of Taichi's close friends outside of the CRC.
- Dogged Nice Guy: For Fujishima.
- Failure Is the Only Option: Is completely aware that his pursuit of Fujishima is this.
- Satellite Character: To Taichi, and, to a lesser extent, Fujishima. He gains more depth as the author begins to develop Fujishima in the later arcs.
- Throw the Dog a Bone: He finally interacts meaningfully with Fujishima in Precious Time.
A student of class 1-A and Yui's close friend outside of the CRC.
- Big Sister Instinct: Towards Yui, who she loves to look after and refers to herself as Yui's older sister.
- Lovable Sex Maniac: Loves to tease the main couples about sex at every chance she gets.
- Love Freak: Manufactures an elaborate triple date for her friends in Step Time just because she was dissatisfied with the intimacy between the couples. Taichi notes how she's starting to rival Fujishima.
- Satellite Character: To Yui, but gains more depth later in the novel.
- You Need to Get Laid: Awkwardly complains how Yui and Mariko do not get intimate with their boyfriends.
A student of class 1-C. She is known for hanging out with delinquents from other classes. Has a crush on Shiroyama Shouto. She did not take it well when Iori rejected the latter and began bullying her with her delinquent friends. She has gone as far as hiring delinquents from other school to sabotage the CRC's presentation. She regrets it though.
- Alpha Bitch: She gets better
- Class Representative: To everyone's surprise, she beat Fujishima in the class rep election for class 2-B and becomes one.
- Curtains Match the Window
- Expository Hairstyle Change: After the events of Michi Random arc, she reforms, cut her hair short and dyes it back to black.
- Green-Eyed Monster: Her crush confessing to Iori pushed her over the edge.
- Hidden Heart of Gold: Thought acting tough would make her crush notice her more.
- Karma Houdini: Lampshaded, everyone is shocked by how easily Iori forgives her, even Setouchi herself.
- She even wins the guy she likes later in the novel. Justified in that she did her best to earn him.
- My God, What Have I Done?: After she finds out that her little revenge tactic went a bit too far. She hated Iori because the latter turned down a boy the former liked rather harshly, and acted very nonchalant about the whole deal. Then she gets a bunch of guys to ruin the CRC's club room, destroying it along with the work they had done for a presentation. And did not approve of the guys kidnapping Inaba to prevent her from identifying them after they were discovered to be the culprits.
A classmate and close friend of Iori.
A mysterious entity and the primary culprit behind the many paranormal phenomena that has been happening to the Cultural Research Club members. He communicates with the club members by possessing and speaking through Gotou Ryuuzen, their homeroom teacher and club advisor. His motives and objectives are unknown except for that he thinks the club members are "interesting" and wants to observe them.
- A Form You Are Comfortable With: Takes control of the club's advisor, Gotou to communicate with the cast.
- Big Bad: The source of the phenomenons and main driver of the events of the series.
- Blue and Orange Morality: Though he sadistically torments the main characters, he also insists that they are benefiting from his phenomenons, too.
- Creepy Monotone: He speaks with zero emotion, making whoever he possesses sound robotic and lifeless.
- Curb-Stomp Battle: Trying to get rough with him is not advised.
- Demonic Possession: How he communicates with the main characters.
- Even Evil Has Standards: Amidst his sadistic abuse of the club members, Heartseed claims to have certain moral policies like Thou Shall Not Kill or how he wouldn't involve an "innocent life." Of course, what is moral to Heartseed may be (and often is) very different from what everyone else considers moral.
- Fluffy the Terrible: "Heartseed" sounds more like a Bath & Body Works shampoo than a sociopathic supernatural entity.
- Humanity Is Infectious: His true desire is to understand humans better. After watching the StuCS change and develop after each phenomenon, Heartseed begins showing more human sentiments, like compassion.
- It Amused Me: The primary motive of his deeds. Maybe.
- "It" Is Dehumanizing: The official translation of the light novels refers to Heartseed this way.
- Knight of Cerebus: Every arc starts off hunky-dory and light-hearted... and then Heartseed shows up.
- Manipulative Bastard: And he's a professional one, at that.
- Non-Indicative Name:Inaba: "What do you have to do with such a lesser known plant?"Heartseed: "Ah........ Who knows?"
- Nothing Is Scarier: Arguably the biggest reason why he is so terrifying is that neither the protagonists nor the viewers ever learn anything about him. We never learn what exactly he is, where he came from, nothing.
- The Omnipotent: He knows all, sees all, and can do just about anything. He claims he can even warp time and space if he wanted to.
- Sadist: Deliberately trying to make a group of friends turn on each just to see what would happen lands him pretty close to being one.
- Sadistic Choice: In episode 5, Heartseed gives the group the choice of which of their souls will die with Iori's body.
- Stealth Hi/Bye: He always seems to pop up wherever and whenever he wants in order to talk with the CRC members. It usually freaks them out when he appears.
- Super Reflexes: Heartseed bestows super human abilities to any body he possesses, allowing even the unimposing Gotou to effortlessly block karate expert Yui's attacks.
- Super Strength: Strength in general is also boosted well beyond what any average human could be capable of.
- Troll: Taken to the logical extreme for someone who has supernatural powers. The struggling and anxiety of the Cultural Club amuses him.
- The Voice: Heartseed never appears in person, and that's assuming he even has a physical form.
Number TwoAnother "Heartseed" who debuts in episode 11, serving as the culprit behind the "Time Regression" phenomenon. It claims to be similar to yet independent of the Heartseed that the Cultural Club knows of. To keep things simple, it chooses to refer to itself as Number Two, as in the second Heartseed. Its motives seem to stem from its fascination of Heartseed's relationship with the club members.
Also worth noting that, unlike the first Heartseed, Number Two doesn't mind being malicious the slightest.
It shows up again in Yume Random, to observe Heartseed. Heartseed is not pleased. And later, in the final arc as well.
- A Form You Are Comfortable With: Just like Heartseed. In the novel, Number Two first appears to Taichi through Ozawa Misaki, one of his classmate, then primary through Taichi's sister Rina for the rest of the arc. In the anime, Number Two appears through Rina right away. Taichi is noticeably distressed.
- Ambiguous Gender: Whether or not the Heartseeds even have a gender is itself debatable, but Number Two does tend to use feminine pronouns when addressing itself and has strictly possessed female characters only.
- Arc Villain: Of Kako Random.
- The Bus Came Back: Two reappears during Yume Random and later the Asu Random arc to aid Heartseed and the StuCS.
- Deliberately Bad Example: The original Heartseed is no saint, but he looks like a Noble Demon compared to Number Two. It actually changes Iori into a baby, right before she could rescue her mother.
- Put on a Bus: The original Heartseed seemingly disposes of Number Two after they disagree over Two's meddling.
- The Voice: Just like the first Heartseed.
Taichi's 10 year-old sister. To Taichi's bewilderment, she's quite knowledgable of love and relationships for someone of her age.
- Adorably Precocious Child: She likes to complain about how busy she is with her elementary school club activities and acts superior to her older brother, as if she is taking care of him.
- Big Brother Attraction: Invoked during episode 14, when she gives Taichi a "true love" chocolate during Valentine's Day. In episode 15, he has a talk with her about how BrotherSister Incest is wrong, causing her to laugh and clarify that she was only joking about the "true love" part. She then kisses him on the cheek and tells him this was her "First Kiss", and Taichi gets really happy.
- Clingy Jealous Girl: Rina really doesn't like sharing her brother.
- Hypocritical Humor: She hates how the Cultural Club is always demanding Taichi's attention and threatens to call the cops on her brother for acting like a lolicon. Ok, you got all that? Go read the above tropes.
- Locked Out of the Loop: Painstakingly so because Taichi dedicates so much time to his sister. It's a challenge for him to keep such a clever kid in the dark about what's really going on. She learns the truth in Asu Random II.
- Sexy Santa Dress: Episode 11.
- Strong Family Resemblance: Looks like a gender-flipped child version of her brother.
- Wise Beyond Their Years: She gives Taichi relationship advice.
Iori's single mother. Although not all of them were marriages, she has been in a relationship with five different men who would serve as father figures to Iori.
- Beware the Nice Ones: Despite coming off as very patient and pleasant, she strikes and chases off her violent ex-husband after learning that Iori wants nothing to do with him.
- Beauty Mark: Like mother like daughter.
- Guess Who I'm Dating?: Reika decides to get back together with her previously abusive 2nd husband, the one that ruined Iori's childhood and forced her to start faking personalities, which is now preventing Iori from speaking up to her mother.
- Horrible Judge of Character: Reika is only doing it because she thinks it would make Iori happy.
- I Want Grandkids: She assumes that Iori and Taichi are having a baby together and is delighted, though she states she was only joking.
- Mama Bear: If Iori is upset or possibly in danger, Reika will take action, sometimes violent action.
- More Hero Than Thou: Reika is willing to put up with her ex for Iori. Iori is willing to put up with her stepfather for Reika. Hmm.
- Parental Abandonment: She tends to work till very late at night, leaving Iori to take care of herself.
- Yamato Nadeshiko: He general nature is patient, kind, and warm. She also allowed herself to stay in an abusive relationship for the sake of her daughter.
Yui's little sister. Surprisingly, she's taller than her older sibling. Tends to mistake situations pretty easily and hilarity ensues.
- Not What It Looks Like: Her reaction towards Taichi, Yui and Inaba carrying a baby and walking with a little boy.
An acquaintance and rival of Yui back in her days of practicing karate. Debuts in episode 11.
- Back for the Finale: Returns in Precious Time to participate in the Couples Battle Royale.
- Curb-Stomp Battle: Gives one to Yui. Of course, Chinatsu has been sharpening her skills the whole time and Yui hasn't, but it was still humiliating for her.
- The Promise: Yui made a promise, which she then forgot about, likely due to her attempted rape, to fight Chinatsu at the national karate tournament.
- Tomboy and Girly Girl: The tomboy to Yui's girly girl.
- Unknown Rival: Yui treats her this way initially in episodes 11 & 12. This only upsets Chinatsu even more.
- Worthy Opponent: Her whole reason for confronting Yui is to make her get back into karate so that Chinatsu can get the chance to beat her.
Aoki's ex-girlfriend and first love from middle school.
- Alliterative Name: Nana Nishino.
- Amicable Exes: With Aoki.
- Cleaning Up Romantic Loose Ends: Aoki seeks out and meets with Nana in order to help himself move on from her. Nana, however, seems to have already moved on.
- Forgotten Childhood Friend: Aoki forgot about her until episodes 11 & 12, after he reverted back to an earlier age and his feelings for her resurfaced.
- Important Haircut: When Aoki came to see Nana for closure, she made a point of mentioning that she'd cut her long hair short back at New Years, possibly to show that she'd moved on with her life; Aoki's reaction to this statement seems to support this.
- Secretly Wealthy: Implied in the novel.
A new addition to the Student Cultural Society after the main cast entered their second year of high school. He is a fellow karate student whom Yui met in the dojo. When he entered Yamaboshi High, Yui convinced him to join the club.
He became the interest of Heartseed in Nise Random, whom gave him the power to disguise himself as someone that the casts know, and requested him to do something "interesting".
- Arrogant Kung-Fu Guy: He's skilled at karate, which has done wonders for his arrogance.
- Bishounen: He's described as quite good looking, even somewhat androgynous.
- Easily Forgiven: One would be surprised at how light the club mates took it regarding the outrageous things he had done to them.
- I Just Want to Be Special: He wishes he had a more outstanding life, unsatisfied with his current self.
- Jerkass: He got better, though.
- Ineffectual Loner: Chihiro's dissatisfaction with life was unwittingly due to pushing others away. It is only after Chihiro begins involving himself more with his peers that he becomes more content.
- My God, What Have I Done?: After his meddling resulted in the memory loss of Taichi and Yui.
- Power Perversion Potential: After receiving the power to disguise himself as anyone he wants from Heartseed, Chihiro has himself a good ol' time messing with the StuCS.
- Pragmatic Hero: Chihiro has no problem cheating if he has to. It's how he defeated Yui during the Sports Festival.
- Tall, Dark, and Snarky: He's considered pretty good looking, but he also tends to look down on others.
- Took a Level in Kindness: Initially full of himself and emotionally distant. Chihiro later becomes much more kind and helpful, though he keeps his irritability.
- Violence Is the Only Option: In Asu Random II, when the StuCS are surrounded by an angry mob of classmates, Chihiro is the first to suggest fighting their way out.
- You Gotta Have Blue Hair
A new addition to the Student Cultural Society after the main cast entered their second year of high school. She decided to join the club because she is in love with Taichi's voice.
She became the interest of Heartseed in Nise Random, whom offered her the power to disguise herself as someone that the casts know, and requested her to do something "interesting". She rejected it at first, but eventually accepted it when things gone wrong and used the power to help.
- Cuteness Proximity: Dogs will always win her over.
- The Cutie: She's described as looking very adorable, like a small puppy.
- Fetish: Shino is absolutely enthralled by Taichi's voice. It can get a little creepy.
- Foil: To Chihiro. Both are dissatisfied with their lackluster lives, but whereas Shino tries to better herself, Chihiro brings others down.
- Heroes Love Dogs: She loves cute animals, but has a special soft spot for dogs.
- Heroic Self-Deprecation: Starts off thinking she's nothing special and fantasizing about being someone more interesting than she is.
- I Just Want to Be Special: Her desire is much more downplayed compared to Chihiro's, however.
- Innocently Insensitive: She tends to unwittingly say exactly how she feels, no matter how insulting.
A student of class 1-C. She is a member of the track team and has a very spirited personality. In one of the short stories in Clip Time, she makes a love confession to Yui and Yui decides to gives her a chance, though she ultimately decides to just be friends.
- Laser-Guided Amnesia: She loses some of her memories due to the Forced Termination phenomenon in Asu Random.
The new student council president of Yamaboshi High. Debuts in the final arc and leads the hundreds of student to stand against Number Three(s)'s phenomena.
- HeelFace Turn: Katori pretty much denounces his antagonism towards the StuCS and becomes an ally by the end of Asu Random II.
- Love Confession: Admits to having feelings for Iori during Precious Time, the final arc of the series. She turns him down since she only sees him as a friend.
- Violence Is the Only Option: After seeing how those who suffer violence are removed from the Isolation Dimension, Katori comes up with the idea that violence really is the only option, and peace advocating individuals like the StuCS better stay out of the way.
- Well-Intentioned Extremist: He's really just trying to help the students escape the isolated dimension and freaky phenomena, however his methods are somewhat... questionable.
Debut in the final arc of the novel as the final antagonist(s) of the series. The culprit(s) behind dragging every first and second year students (except the main cast) of Yamaboshi High into their large scale experiment. Not exactly a single entity but rather how the main cast decided to call the unknown number of Heartseed(s) that took part in the phenomenon after they learn of their presence.
- A Form You Are Comfortable With: As per Heartseed tradition, Number Three always appears while possessing a student.
- An Even More Deliberately Bad Example: As if Number Two wasn't already bad enough, Number Three(s) dragged pretty much two thirds of the school into an isolated dimension so they could "better experience the amusement."
- There Is Another: You thought Number Two was the last of them?