Our protagonist. He's lighthearted, casual and prone to joking around, but he isn't close to anyone apart from Kotori and Yoshino. Beneath the jocular exterior lies a depressed person trying to rework his personality into someone who can form deeper relationships. Fortunately, he's mostly succeeded in this by the start of the series, though he doesn't take people seriously enough.
He conceals the power to "rewrite" himself, strengthening his abilities.
- Alien Blood: In Moon, his blood is greenish red presumably because in Moon he starts out as basically a familiar thanks to the merging of all his possible selves.
- The All-Concealing "I": When memories of his past come up a lot of details about him are left pretty vague which is elaborated on in Terra. Namely, he's about six years older than he seems.
- Ambiguous Disorder: The game implies he might have mild Tourette's Syndrome or high-level Aspergers through his inability to process emotional feedback and continually say the worst possible things at the worst possible times.
- Badass in a Nice Suit: In the Akane Route he becomes her primary assistant and gets to wear a rather nice suit while doing so.
- Bloody Murder: Aurora smells faintly of blood and works better if his wrist has been injured. Terra reveals that originally his power was to manipulate bodily fluids, including blood. In the character routes, the ability has been upgraded.
- Break Her Heart to Save Her: In Terra route he guns down Kotori's familiarized parents in front of her after she admits tearfully that she's stayed with him and the Key this whole time because she just wants to enjoy the festival with him like he promised. He even gloats. If he hadn't, not only would she have followed him into what he viewed as a suicide mission, but she also would have kept those same fake parents around. With them around, she would both fail to move on and drastically cut into her own life span.
- Brilliant, but Lazy: In Terra route when he was in Guardian he refrained from using his power and as such had the lowest test scores of his entire group, though his experience and level headed behavior tended to make up for it. As anyone who has read up to this point knows, if he actually goes full throttle he is far beyond any other superhuman.
- Brought Down to Normal
- In Kotori's ending he loses his powers apparently as a consequence of Kagari using her dying moments to take them away.
- In Akane's endings his powers fade away after he first overuses them and then enters a sealed space without the life energy used to power them.
- Call-Forward: In Terra, we can see the proto gadfly Kotarou when he tricks a young Yoshino, though he doesn't recognize this part of his personality amongst all his angst.
- Cannot Spit It Out: In Lucia's route if Kotarou had just bothered to explain why her poison didn't work on him a lot of misunderstandings could have been cleared up. On the other point of Lucia wanting him to say he wanted to be with her out of love and not pity he can't be blamed, however. He did say it, but it apparently didn't count the first time.
- Cast from Hit Points: Kotarou worries that using Rewrite may work like this. The answer is yes and no and the severity varies by route. Normally, it would tap heavily into his life force, though really overdoing it would turn him into an immortal familiar like being. Normally this isn't a problem thanks to Kotori adding a piece of the Key's ribbon to him and setting up a contract that connects him to a wellspring of life energy. However, in Terra route, he avoids the incident that nearly killed him and has to rely solely on his own life force. Despite rewriting himself little more than in the other routes, he is on the verge of death via lifeforce expenditure by the end.
- Casual Danger Dialogue: When nearing the end of the Asahi Haruka curse investigation, he reacts to the glass covering a photo of her breaking with a response boiling down to "Well, everyone gets embarrassed when someone sees an old picture of them." He even means it. Why not? He knows Lucia wouldn't really hurt him.
- Catchphrase: Whenever Kotarou makes a friend, he shouts "Amigo!"
- The Charmer: Kotarou is capable of talking people into doing rather silly things. Yoshino calls it his skilled conversationalism with a great deal of irritation while Kotori is extremely impressed when he gets Chihaya to believe complete, utter nonsense about the spicy parfait challenge.
- Chivalrous Pervert: The best way to sum this up is that he makes a bet with Akane that if he can prove the supernatural, he gets to touch her breasts. However, to him, this is basically equivalent to 'And thus you will go out with me' rather than just being a chance to grope her. Fittingly, to be able to prove the supernatural you have to aim for Akane's route.
- The Chosen One: Unlike most superhuman "Eyes," Kotarou's ability to perceive the Key is solely due to his presence at its "birth." His meeting with the Key kicks off the events of Rewrite and places him at the center of the story though this usually means he screwed up.
- Combat Pragmatist: Kotarou is efficient and brutal in Akanes route to make up for his lack of pure ability.
- Deceptive Disciple: A positive version of the trope. Esaka is his supporter and mentor and Kotarou truly respects him, but he betrays him and uses his position in Guardian to steal information. In the end, he kills Esaka in a duel.
- Determinator: In the Chihaya route Kotarou is a pretty straight shonen hero, determinator status included. In other routes this also holds up.
- Dismotivation: Kotarous attempts to improve his life are so half-hearted that they disgust Yoshino. He apparently doesn't even know the names of most of the classmates he acts all friendly towards because he doesn't consider them worth his time, putting in doubt how much he really wants to get along with everyone.
- Does Not Know His Own Strength: After rewriting himself before the story begins, he began breaking stuff on accident if he doesn't watch his own strength. Before going into Akane's room for the first time he breaks the lock and Kotori mentions a faucet he broke before. It's one of the early hints that there's more to him than there seems.
- The Dragon: To Akane in her route, after the one year timeskip.
- Energy Weapon: He learns how to create "aurora," which he usually fashions into claws or a sword, at the end of most versions of the Common route. He only manages this at the very end of the Lucia and Terra routes.
- Everybody Knew Already: Kotarou tries to hide his Rewrite ability, but certain people figure it out immediately.
- Sakuya knows at a glance that Kotarou can rewrite himself because he used to have the same power.
- Akane's route and Moon indicate that Akane knows Kotarou's true age and who he used to be. Why not? He saved her as a little girl. She apparently used her abilities to wake him from his coma and alter his memories, leading to the present.
- Terra retroactively shows that Kotarou's attempts to hide his powers from Esaka, Nishikujou and Imamiya were a waste of time. He knew them six to ten years ago when he was in Guardian.
- Also in Terra, Kashima Sakura figures out he's a superhuman... but she doesn't care, because he's not associated with Guardian.
- Explaining Your Powers to the Enemy: Generally averted. Kotarou hates telling anyone what his ability is, especially in Terra. At one point he tells Esaka that he has the ability to stop himself from bleeding. While true, this is obviously not his power. And Esaka is a friend, meaning everyone else gets even less information than that.
- Foreshadowing: There are a lot of hints that Kotaro is older than he seems in the character routes as well as a former Guardian agent.
- His older neighbors are puzzled with him since they remember him being five to ten years older while newer neighbors treat him like normal.
- When Kotarou talks in passing about a popular tune from his childhood his peers don't recognize it at all but Nishikujou does.
- Characters like Imamiya and Esaka look at Kotarou oddly and have some curiously about him even though he doesn't know them at all.
- The Gadfly: Kotarou likes to pick on people, especially the likes of Yoshino or Chihaya, though nobody is safe.Shizuru: What was the point of that?Kotarou: I just wanted to make you meow.
- Generation Xerox: He has a lot in common with Sakuya.
- They share the Rewrite ability, and both of them gave everything they could to protect a single person. In Shizuru's route, like Sakuya, he fails to stop Salvation and becomes a tree, but his girlfriend made it through.
- In the Terra Route Kotarou does the exact same thing Sakuya did, and rewrites himself into a tree after he fails to protect his love. There's even a short scene right before, where he talks to Sakuya's spirit, and Sakuya mentions that Kotarou has now "taken his place completely". Sakuya ceases to exist completely.
- Healing Factor:
- Kotarou heals quite quickly after he rewrites himself enough to use Aurora.
- In Chihaya's route, he increases his regeneration in order to beat Midou the summoner. Sakuya dryly notes afterward when Nishikujou attacks him that she'd have to cut him to ribbons if she wanted to kill him.
- Heroic RRoD:
- In Shizurus route Kotarou does even more rewriting on himself and the downsides finally begin to appear as his body begins minor mutations. Its subverted near the end, however: Overuse causes immortality, not death.
- In the Terra route, Kotarou uses his entire lifespan as fuel for Rewrite. To stop himself from dropping dead right there so that he can get to Kagari, he rewrites his body one last time knowing it will make him a quasi immortal existence like Sakuya.
- Identity Amnesia:
- Kotarou has some slight memory difficulties at the beginning of the story apparently as a result of a long illness. He's pretty fuzzy on the details of his illness, but he remembers enough of when he was young to know that he doesn't want to be the depressed loner that he was at his core. He was a member of Guardian, but was almost killed when he tried to attack Kagari. Kotori used her powers to save him and he went into a coma. After being injected with Guardian's memory erasing drug, he forgot most of his past. Freed from that baggage, his personality changed like he had always wanted it to and he goes from the gloomy loner to the cheerful Kotarou that appears in the main story.
- Again in Terra Route's ending. The heroines decide to name him Pochi.
- Intelligence Equals Isolation: In Moon he attempts to rewrite his mind rather than his body in order to understand the theory of life that Kagari is working on. Since he seems to have a better idea of what to do than when he tried it before the story started, it works... but it leaves him feeling cold, unhappy and isolated. He reaches a point where he understands that love is a lie, which Sakura Kashima reached and despaired over, but then continues from there and finds it again on another level, at which point he returns more or less to normal.
- Kind Hearted Cat Lover: Kotarou enjoys feeding the local cats, especially the one that always hisses at him before taking the food he offers.
- Living Emotional Crutch: During Moon route, Kagari becomes a crutch for him because there is no one else around and he can't take solitude. He convinces himself that their relationshipnote is sacred and precious. When he finds more people to talk to, suddenly he's not spending much time with her.
- Malicious Misnaming: Sakuya constantly insults Kotarou by getting his name wrong. Fatarou (Yotarou) is his favorite.
- Mundane Utility: Kotarou decides that the blades he can manifest from his wrist are not suited for cooking. He did try though!
- Never Gets Drunk: Kotarou notes early in Terra that he can't get drunk and thus drinking holds little appeal. Most superhumans also break down alcohol too quickly to feel any effects from it.
- Nice Job Breaking It, Hero!
- In Shizuru's route, Kotarou's carelessness gets Shizuru disabled for the majority of the fight with Gaia. Since she's one of their best fighters, Guardian is too late in getting to the Key and only barely manages to evacuate anyone into their shelter. The world is reduced to a known population of fifty people by the time they exit as well as Kotarou in tree form, who can probably turn himself into a human form again.
- Kotarou sides with Akane without really questioning what shes doing. It's made clear that this is very stupid before any consequences show up. She sets off the apocalypse. The story really seems to enjoy pointing out just how badly Kotarou screwed up, especially when it was obvious that he could have stopped it.
- Not Now, Kiddo: Nobody takes his claims of being haunted seriously. If they had, they'd have found the Key in ten minutes. Kotori knew what was going on but didn't want to think about it. Akane may have figured it out, but did nothing.
- Oblivious to Love: Shizuru is apparently not even a blip on the radar throughout the common route unless you're pursuing her ending, at which point he's not sure a relationship would be a good idea. Nor is Lucia despite her extremely tsundere attitude. He has his suspicions about Kotori, though, despite her doing everything she can short of saying 'I don't like you.'
- Older Than He Looks: He's in his mid-twenties, having not physically aged much since becoming a half-familiar.
- Plant Person: His fate in Shizuru's route, in which, like in Sakuya's backstory, he becomes a plant as a result of using the Rewrite power to survive the end of the world.
- In Moon, there's an odd sequence where a temporally displaced Kotarou sits still for a few months and slowly begins forming roots into the ground. Leaves grow out of his fingernails.
- Overuse of Rewrite will eventually turn him into a familiar in the shape of a tree, though he can assume a human form again.
- Power at a Price: Continued use of his power uses up his lifespan and slowly transforms him into a familiar.
- Power Glows: Apparently, Kotarou glows sometimes when he rewrites himself. It's not a consistent effect, however, depending on the writer. For example, when rewriting himself in Lucia's route no one comments, but in Chihaya's route or Terra they do.
- Power Incontinence: Kotarou's Rewrite ability only has an on switch. There is no off, so thanks to some rewriting he already applied to himself he can no longer do anything like participate in sports without drawing major attention.
- Reality Warper:
- In the Moon Route, he obtained a weak version of this from reading the theory of life. He used it to do some experimenting and summon all the friends he made throughout the story.
- In the joke ending, he rewrites the world so that humanity worships boobs.
- Second Year Protagonist: He's a second year high school student.
- Shapeshifter Weapon: Aurora. Kotarou spends a lot of time investigating its limits in Kotori's route. Other routes he just makes it up as he goes along.
- Staking the Loved One: He's forced to kill Kagari at the end of Terra route in order to stop Salvation. It was no longer necessary but could not be stopped. In a way, the only reason for keeping Kagari alive was to figure out if they were on the right track for preventing humanity from destroying itself, which is what would happen if she were killed earlier.
- Stalker with a Crush: Kotarou toes the line sometimes when it comes to Kotori. He follows her around as much as he can, right up to but not past the point where she'll start avoiding him.
- The Starscream:
- After he finds out the true nature of salvation, he betrays Akane in order to save her and the last vestiges of humanity in Kazamatsuri.
- He's also a Starscream to both Gaia and Guardian in the Terra Route where he works to bring down both organizations from the inside in order to help Kagari.
- Stepford Smiler: Kotarou acts all friendly and happy, but he's actually pretty frustrated with his life and looks down on his peers.
- Stupid Sacrifice: After rewriting himself to not be a drain on Shizuru, Kotarou decides to stay for the end of the world for some reason. However, it turns out he did survive and while it seems hes still a tree, Chihayas route shows that this is actually not permanent.
- Supernatural Is Purple: The more Kotarou rewrites his body, the more the meter at the bottom left turns from blue to purple.
- Synchronization: After Shizuru barely manages to save Kotarou, the two become linked.
- Tomato in the Mirror: Kotarou asks Kotori if hes a familiar. She doesnt know, but suspects the answer is yes. The correct answer iiiis: Not quite. He really didnt die and thus isnt a familiar, but his body is sustained like one. Also, the reason he's like that doesn't have much to do with Kotori, but she wouldn't know that.
- Took a Level in Badass: His Rewrite ability's whole schtick is pretty much this. By concentrating, he can increase the effectiveness of his body's abilities, though he can't tone his strength, speed or other abilities back down afterward. In Chihaya and Akane's route as well as Moon and Terra we see just how many levels of badass he can push himself through.
- The Trickster: Though many of his pranks tend to backfire, especially against Lucia.
- Vague Age: It's not really clear how old he actually is, which only comes up in Terra. Everyone else's age is also pretty vague. The Friends section says that Kotori is ten years younger but this doesn't actually match up with the facts. This isn't helped by how much time passes, either. He graduates middle school at the beginning of Terra but then there's apparently a five year timeskip that goes unmentioned. Any guess about his age could range from five to ten years older than Kotori and the others.
- Vitriolic Best Buds: Kotarou pretends that he and Yoshino are best buddies, but Yoshino really is pretty pissed off with how Kotarou behaves. They are friends to an extent, though.
- Weaksauce Weakness: His aurora blades cannot cut through konjac. No, this doesn't come up again.
- Why Did It Have to Be Snakes?: He's extremely uncomfortable about the idea of supernatural phenomenon, which isn't helped by the fact that he knows at least some are real. Naturally, he ends up joining the occult club.
- Willfully Weak: Kotarou's power allows him to be physically stronger than most of his classmates. He chooses to not draw attention by rarely strengthening himself.
- Wistful Amnesia: In Terra Kotarou has a very, very vague idea of the path the world will take due to Moon Kagari planting inside him a tiny piece of information. It's so minor he isn't even aware of it. It allows him to make the perfect decision in every meaningful junction of his life and leaves him with odd feelings. For example, he halfheartedly tries to stop Kotori's parents from leaving on the trip that will kill them and has an unnatural attachment to Akane. It's also responsible for his attachment to Kagari.
- World's Strongest Man: Potentially. Should he rewrite himself enough, his potential has no real limit. Doing so would probably not be a very good idea, however.
- Wrong Genre Savvy: He frequently thinks of the world in terms of RPG Elements, including Character Level, "______ joins the party" when he is recruiting members for the club and how Lucia's punches deal 9999 damage.
Kotarou's childhood friend, and an expert gardener. She has a habit of taking naps out in the forest. She's able to play along with Kotarou's attitude and jokes rather effectively, but is oddly resistant to any insinuations that she and Kotarou are an item and if he jokes too much about it he risks her withdrawing.
- Bad Liar: When Kotarou tries to utilize her in his tricks her lies tend to be really transparent. In truth, she's actually rather good at lying and hiding things.
- Blank White Eyes: Kotori is frequently seen surprised with blank eyes.
- Bratty Half-Pint: Kotori was kind of a jerk as a little kid, although she's more in lines of a Nice Girl now.
- Break His Heart to Save Him: She rejected Kotarou's love confession before the story began and does so once again in her own route. Even in her own route, Kotori transfers out of school without telling Kotarou because she is hiding Kagari from both Gaia and Guardian. She knows that it is a hopeless struggle and she would most likely die when found, so she keeps herself distant from Kotarou to protect him. Doesn't stop him, anyway.
- Celibate Heroine: She rejected Kotarou once before, but she didn't want to part from him. In her route, he tries confessing again and she explains that she has no intention of falling in love with anyone else or anything, so she'll just stay alone. She likes Kotarou, but think he might be her slave. Furthermore, she's probably going to die young.
- Childhood Friend Romance
- Kotori is one of the available heroines. Interestingly enough, she shows little interest in the idea leaving Kotarou to be the one enthusiastic about the idea. He actually confessed to her before, but got turned down for several reasons, none of which is not liking him. First, she thinks he might just like her because he's possibly her familiar. Second, she worries that she might have 'killed' the original Kotarou and created this happy go lucky version. Third, her survival is highly unlikely and she doesn't want him to feel that loss.
- In the route that unlocks after Kotoris she seems a little left out and sad, possibly because the events of the route show her that Kotarou didnt confess to her because of the devotion a familiar feels.
- Cool Pet: Chibi-Moth, a pygmy mammoth familiar.
- Druid: Kotori, despite clearly despising Gaia's agenda, is a descendant of sorts of a group that would choose to protect the Key. In fact, the druids were once closely allied with them, but they seem to have died out.
- Decoy Protagonist: She is the face character of the game but her role is pretty small in the big picture. She's having more to do with the past than present. Of course, she still has her own route but pretty much disappears in every other routes but Moon and Terra. And everyone knows Kagari is the true heroine.
- Epic Fail: How she describes a Bad End.You understand, right? If we get a Game Over here, we won't just go back to the title screen. The disk explodes in a little fireball.
- Everyone Can See It: It's a minor Running Gag at the beginning of the game that everyone thinks that she and Kotarou are already a couple.
- Flower in Her Hair: Two of them, fitting her expert gardener status and that she is a Druid.
- Gold Digger: She claims that she wants Kotarou to make more money before their relationship can go anywhere.
- Gratuitous English: Shake it now baby now!
- Green Thumb: She's popular in town because pretty much any plant she touches springs to life. The Gardening club even workship her for her incredible ability.
- Happily Married: Her ending in Harvest Festa. She and Kotarou got married after their graduation from high school.
- Idiot Hair: She has one hair perpetually standing up and constantly acts like a complete dork.[[She is secretly a genius though]]
- I Want My Beloved to Be Happy: Kotori rejected Kotarous rejection before because she knew she probably couldnt have a normal life. And also because shes not sure if he loves her because he genuinely cares about her or if he might be a familiar programmed into loving her. Either way, she feels it cant work. In the route that follows this, she realizes it wasn't because he was a familiar, but now it's too late. It's implied that helps tie Kotarou to Shizuru instead of her herself after this.
- Money Fetish: Early on, Kotarou gets her to sleepwalk forward by jangling spare change in front of her. She also laments that girls can't get married when seeing how wealthy Chihaya is.
- Nice Girl: A sweet, kind, and caring young girl.
- Sleepyhead: Kotori spends most of her time in class sleeping. Shes working herself to death trying to protect the Key from either Gaia or Guardian getting her and has been doing herself for ten years. Small wonder she spends a lot of time sleeping.
- Smarter Than You Look: She spends most of her time in class sleeping unless she's hanging out with Kotarou. However, she's actually very intelligent and perceptive and just likes goofing around in her spare time. For her, that means during class and eventually during the occult club. When she was a kid she was a bit of an Insufferable Genius due to having been bullied, however, but mellowed out as she got older and gained more responsibilities.
- Stepford Smiler: Partially Overall, at school and whenever she's with Kotarou and Occult Club's members, she is super energetic and cheerful. She seems to enjoy herself so much not only because school and friends are wonderful breaks from the tediousness and loneliness of her Druid job but also because she doesn't want anyone to notice and worry, especially Kotarou.
- Tragic Dream: Kotori initially got her powers in an attempt to revive her dead parents. She tried her best in upholding the contract to protect Kagari, but she later realized that her "parents" were no different from zombies that moved to her commands.
A first-year student and acquaintance of Kotarou. As a self-proclaimed "moral guard", she carries around a whistle to call out students on rules violations. While she is very serious and normally quiet, she also enjoys playing along with Kotarou's pranks. In fact, due to a rather obvious crush, she generally supports Kotarou in whatever he does. She wears an eyepatch, but at the start of the story Kotarou doesn't know why.
- A-Cup Angst: Shizuru has a mild dissatisfaction about being so short and flat. Kotarou thinks she could pass for a sixth grader. Not that he'd say that.
- Action Girl: Shizuru is a front line fighter.
- All of the Other Reindeer: When she was a lot younger, she left her golden eye uncovered and got bullied for it. Since then she keeps it covered.
- Badass Adorable: Shizuru is probably the strongest character in the main cast at the start of the story. Kotarou can make himself tougher than her, though he normally doesn't, and under certain conditions Lucia can beat her.
- Cat Smile: Frequently, usually whenever enjoying her saury.
- Combat Medic: Her main ability can create different kinds of medicine; she is also one of the strongest fighters of the group.
- Comically Serious: She plays along with Kotarou's jokes as much as Kotori, but unlike her she always looks completely serious.
- Cute Mute: She's generally very quiet, leaving Kotarou to interpret the facial expressions she makes for a large amount of their conversations. She later loses her voice when she formed a contract with Kotarou. Everyone believed she was just acting normally and thought it was adorable.
- Dodge the Bullet: She can drug herself into moving and reacting so quickly that a hallway filled with bullets is a cakewalk to move through unscathed.
- Extreme Omnivore: One of the lighter examples. She'll eat plants she finds in the forest or insects that she runs across. Well, only probably for the latter because Kotarou dares not turn around to confirm it. The things she was eating were perfectly safe to eat, but even if they weren't Shizuru is immune to poison and disease.
- Eye Scream: Subverted. Beneath the bandage is a perfectly functional eye, it just happens to be a different color and attracts unwanted attention. But when she was young? Yeah. Took some debris to the face but since she has a healing factor it wasn't a big deal.
- Freakiness Shame: Shizuru wears an eyepatch not because her eye is damaged, but because she has heterochromia. Kotarou tells her that her golden eye is pretty.
- Gamer Chick: Downplayed. She doesn't play often anymore, but due to playing a lot as a child, she is easily able to defeat Kotarou in fighting games.
- Girlish Pigtails: Kotarou seems to identify her by her hair a lot of the time. He considers the twintails to be a rare spawn monster at one point.
- Hair of Gold, Heart of Gold: Has blonde hair, and is one of the nicest characters in the series.
- Healing Factor: Shizuru produces medicines and drugs in her body and can heal herself quite quickly. She can also heal others.
- Healing Hands: She can heal people directly as well as produce medicine inside her body.
- Humble Hero: Despite earning a lot of money working as a Guardian, she refuses to spend the money on luxuries and instead live in a simplistic tiny house. Apparently, she's saving up money to buy her parents a dream home once they finally remember her.
- Jack Bauer Interrogation Technique: Threatens Brenda with this.
- Knife Nut: In combat, she dual-wields knives.
- Laser-Guided Amnesia: Shizuru has the power to control memories to an extent.
- Literal-Minded: Shizuru gets some rather odd imagine spots at times due to not getting a lot of metaphorical speech.
- Mark of the Supernatural: Her eye is golden because she regrew it improperly after it was destroyed by debris. This was one of the first really noticeable uses of her superhuman power to heal.
- Nice Girl: She has a kind, polite, and an adorable personality, as evident with her interactions with Kotarou.
- Nonverbal Miscommunication: Played with. Kotarou likes attaching random meanings to Shizurus expressions when shes being quiet and in truth even he thinks theyre complete nonsense, but it turns out hes actually frequently right.
- Power Incontinence: When she was little, her control over her ability was not as refined and she accidentally wiped herself from the memory of her parents.
- Puppy-Dog Eyes: Shizuru is quite the master of beseeching looks.
- The Quiet One: Shizuru isnt silent, but a large amount of her communication is just Kotarou reading her expressions.
- Reading Lips: She knows how to read lips which helped when she lost her hearing.
- Secretly Wealthy: Shizuru would be a millionaire if you converted yen to dollars, but lives in a tiny, empty building and eats extremely cheap food. Apparently, she is saving up money to buy her parents their dream home after accidentally wiping out their memories, showing that she still cares about her parents.
- Sleepyhead: She tends to sleep in very late if she can and can often be found dozing in the courtyard at school when she has the time. It's indicated that this may be partially a result of her abilities.
- Token Mini-Moe: Kotarou thinks she could pass for a sixth grader with the right clothes. She's very short and young looking and is mildly irritated over it.
- Trademark Favorite Food: Saury. It reminds her of her family, though she always liked it.
The Class Representative of Kotarou's class. Kotarou seems to think of her as the stock uptight Class Representative character. She's one of the more stereotypically violent tsunderes. In combination with her perceived neat freak attitude such as always wearing gloves she doesn't really have any friends apart from Shizuru. She has a reputation for a high tolerance to spicy foods.
- Action Girl: She has rather high physical strength and doesn't hesitate to use it.
- Bad Powers, Good People: Lucias abilities are making concentrated death and destroying things. Shes a little heavy on the tsuntsun but otherwise a perfectly kind person.
- Big Bad Friend: Lucia keeps trying to get Kotarou to drop the Asahi Haruka investigation because she is Asahi Haruka. She hasn't done anything wrong, though.
- Blank White Eyes: Lucia gains blank white eyes on occasion whenever Kotarou does something particularly surprising.
- Cerebus Retcon: Lucia's tolerance for spicy food is played for laughs. In her route, you learn that she's actually incapable of tasting spicy food because of the drugs she is taking to suppress the deadly poison in her body.
- Class Representative: Kotarou thinks of her as the classic uptight class rep that's obsessed with order and is convinced every school probably has their own Lucia in charge of a class.
- Collateral Angst: Rather than dwell on the people accidentally killed Lucia gets the lions share of the sympathy points in that story while Kishida Ryuugo and the nurse are largely forgotten. Later, Lucia intentionally kills two hundred thousand people and again the story focuses on her depression.
- Cordon Bleugh Chef: She can cook, but when Kotori offers to swap items from their lunches Lucia declines because her meal was made more to look good than to taste good. Coupled with her extreme tolerance for spice it's questionable whether it was truly edible for anyone but her. She has no sense of taste. She just has excellent control over how she perceives the world and if food looks good she can stimulate her brain into remembering how things tasted back when she did have a sense of taste. Thus, what she considers good food and what others consider good might very well not overlap in the slightest.
- Demonic Possession: Subverted. Lucia pretends that Haruka is speaking through her mouth, but its pretty obvious that the two are the same person. Its confirmed not much later.
- Don't You Dare Pity Me!: She doesn't want Kotarou to stay with her just because he pities her cursed touch. She wants Kotarou to actually love her.
- Friendless Background: When she was young she never had any friends. She still only has one friend at the start of the story, Shizuru.
- Full-Name Ultimatum: Whenever she puts distance between herself and someone else she ends up referring to them by their full name, especially TENNOUJI KOTAROU!!
- Hair Intakes: Her hairdo has two of what look like cat ears.
- Hair-Trigger Temper: A lot of her tsuntsun behavior is actually more a result of her being really easily angered rather than her necessarily covering up embarrassment or affection.
- Healing Factor: Not most of the time, but in an area filled with the poison she makes she possesses a healing factor even stronger than Shizuru's.
- Katanas Are Just Better: Despite the fact that a sword really isn't the most efficient of weapons, it's the weapon she favors. She can't use guns, after all. Also, with her vibration powers her attacks are much more effective.
- Megaton Punch: Lucia is fond of decking Kotarou when he does something that at least looks perverted. She eventually promises to stop mid route.
- My Sister Is Off-Limits!: She's not Shizuru's sister, but because of her overprotectiveness the rest of the club starts thinking of her as Shizuru's sister in law when Shizuru and Kotarou start getting closer.
- Neat Freak: She has a reputation as a neat freak thanks to the white gloves she always wears. It causes her some social problems because when she has to touch living things she begins calling everything filthy and absolutely refuses to do so. She actually considers herself filthy: Touching a cat even through the gloves could be putting it in danger if it touches her wrist or anything.
- Only Friend: Shizuru is Lucias only close friend. Only she can resist the toxins that Lucia continuously creates.
- Out, Damned Spot!: She has a nightmare where she compulsively washes her hands because they keep oozing poison. When Kotarou sees her without gloves her hands are perfectly normal or even pretty. Still, given her neat freak thing, it's pretty easy to understand but it is really true. You just can't see the poison.
- Poison Is Corrosive: Anything receiving a sufficiently high level of poison will blacken and crumble within seconds.
- Poisonous Person: Lucia has nightmares where her touch is so filthy and impure that it causes anything she touches to wither, rot and die. Thanks to experiments designed to allow Lucia to survive in toxic environments, she herself releases a poison that kills all living beings that touch her. She can control it somewhat, but not turn it off entirely. And thats with suppressants.
- Power Incontinence: She tends to break complex things around her thanks to her vibration ability. She also breaks people, animals, plants and bacteria since she's a poison factory.
- Psychic Powers: Apart from her poisonous touch, Lucia has mild telekinetic abilities, though they're not very useful.
- Sensory Overload: An inadvertent example. After she stops taking the suppressants that dull all her senses she perceives the world much more strongly than usual, causing her to feel overloaded, drained and slightly feverish. It cuts into her date with Kotarou but not as much as when she poisons the town moments later, killing every leaving organism inside that lacks protection. It's implied that her holding in her poison may have been what was really responsible, making it a possible invocation and subversion.
- Super Hero Origin: Lucia doesn't seem to be a normal super power user like Shizuru or Kotarou. Rather, her poisonous person abilities and vibration power are the result of an experiment performed on a large amount of orphans. She was the only survivor.
- Superpower Meltdown: Lucias suppressants stop working in every route, after which she has to live inside bunkers until a new one can be developed. In her own route, her body is fiddled with so that she makes even more poison after this. This already makes her unsafe to be around for anyone but Kotarou or a few special individuals, but then shes manipulated into setting them off. The entire town of Kazamatsuri is killed. Plants, animals and people. In theory, even the bacteria are dead.
- Touch of Death: In a nightmare that she has, things Lucia touches with her hands die. Shes worried that it happens for real, but its noted that it was just a string of bad luck that gave her classmates that impression. Turns out she really does have it and can only really minimize the effects.
- Trademark Favorite Food: Lucia has a reputation for loving spicy food and seems confused when people react with shock to her enjoyment of it. She has no sense of taste.
- Tsundere: Kotori catches on pretty quickly to Lucia's attitude. It's partially intentional since shes interested in Kotarou but has only partial control over her abilities, so she tries to keep him distant from her. Not that its entirely a pose, as she quickly makes clear.
- Walking Tech Bane: Lucia destroys anything like complex machinery quickly when she touches it, so for the most part she cant normally use stuff like that without taking some form of suppressant. She cant even reliably use a gun.
- Walking Wasteland: As a result of Guardian's experiments, and the reason she wears gloves.
- You Gotta Have Blue Hair: Lucia's hair is dark purple.
President of the Occult Research Club, and the "mysterious witch" of the school. She's very aloof from the group and only interacts frequently with Kotarou himself and to a lesser extent Chihaya and Sakuya. She's quite fond of teasing Kotarou. Like Chihaya, she doesn't seem to have had any friends prior to the story beginning. Unlike Chihaya, she's still not very good at it during the story.
- Agent Scully: Appears as one, but is actually maintaining the Masquerade by erasing any evidence that Kotarou finds.
- Big Bad Friend: She's one of the leaders of Gaia and the direct subordinate of the real boss. Gaia has at least two major factions and Akane's is the one that wants to end the world, though she doesn't seem thrilled about it. However, despite this, she persists. In Chihaya's route she apparently prevents the Song of Salvation, but then goes nuts when she sees all the bad memories of mankind and nearly ends the world herself. In both her own and Shizuru's route she succeeds.
- "Blackmail" Is Such an Ugly Word: It's magic, honest!
- Brilliant, but Lazy: She's quite clever and witty, but she hates exerting herself. She doesn't even seem to go to class for exams, making it unclear why she goes to school at all.
- Club President: She's officially the leader of the Occult Club, though it was actually already disbanded. Plus, Kotarou tends to be the one who actually tries investigating occult stuff.
- Curtains Match the Window: She has yellowish-white eyes and hair.
- Friendless Background: The idea of friends is something that's rather foreign to Akane. She seems slightly bemused that she actually cares about people like Kotarou.
- Gamer Chick: Almost never seen in the club room without her laptop and playing games.
- Go Mad from the Revelation: In Chihaya's route, Akane manages to capture Kotori and the Key. Right when she's deciding that she doesn't need to cause the end of the world anymore, the Key shows her the worst memories of mankind and she goes absolutely insane. Shes furious that the Key saw enough good that it decided not to wipe out humanity and decides to do it herself.
- Hikikomori: She hates going outside or interacting with new people.
- Lazy Bum: She hates having to go out and meet people.
- Not So Above It All: Akane likes to act as the Only Sane Man, but even apart from her obvious eccentricities shes really determined to disprove anything occult based due to the groping bet made at the beginning. The lengths she goes to for this are quite impressive. She also joins in on the antics occasionally despite her protests.
- Ojou: She was adopted by an old, influential woman with ties to the Martel Corporation. Whenever Kotarou catches her by surprise, though, she's usually ruining whatever dignity and elegance she has. She's also fairly vulgar.
- Only Sane Woman: Akane, despite calling herself a witch, is the only one with a firm grasp on reality. She's also the only one who seems to really notice what a bunch of weirdos have gathered in the club room. It later turns out that her 'firm grasp on reality' thing was her covering up incidents that she actually knew to be true while exposing those that were genuinely fake.
- Reluctant Psycho: She does not really seem to enjoy her job and faces it with sheer resignation. When she wins in Shizuru's route, she's depressed. She does not really want to become the Holy Woman either and when she inherits the job in her route she starts slipping quickly under the weight of the inherited grudge despite knowing and hating what she's doing.
- Screw the Rules, I Have Money!: She abuses her wealth and influence to get credits even when not attending classes. She also gave her secretary a teaching position in school.
- "The Reason You Suck" Speech: Is on the receiving end of a harsh one from Koutarou.
- Transferable Memory: Her ability to "heal" people with broken minds is really just turning a part of their brain into a familiar. She then transcribes some of her memories to "fix" them.
- You Gotta Have Blue Hair: Akanes hair is some whitish yellow color.
A new student who transfers to Kotarou's school and class early in the story. Prior to transferring she had never really had any friends and can be a little awkward around others. This is not helped by her both being an obvious tsundere and not being terribly intelligent. She also appears to be quite wealthy and has a seemingly perfect personal butler named Sakuya to attend to her.
- Action Girl: She has immense strength, but doesn't directly most of the time.
- Big Eater: Chihaya eats constantly. Kotarou figures that the constant eating is how she manages to keep her strength up since shes not particularly muscular. He's wrong.
- Blank White Eyes: Frequently; possibly more often than the rest of the cast combined.
- Butt-Monkey: Chihaya is the butt of numerous jokes.
- Cute Clumsy Girl: Presumably because shes so strong and durable that she doesnt need to worry about being careful.
- Delayed Reaction: Chihaya has a tendency to not react to things properly until a bit of time has already passed.
- The Ditz: Kotarou loves teasing her because she's not very smart.
- Does Not Know Her Own Strength: If she stops paying attention she throws too much strength into her activities and risks breaking things. However, this rarely happens.
- Doomed Hometown: She is from a village of summoners, which was razed by Guardian when she was a child.
- Friendless Background: Kotarou is her first real friend.
- Friend to All Living Things: Chihaya can get along well with the legendary Hissy Cat. She indicates that she's used to this sort of thing.
- Hair Decorations: Chihaya has wings in her hair.
- Idiot Hair: She has one hair perpetually standing up.
- Improbable Weapon User: At one point, she uses a telephone pole to fight off several familiars.
- New Transfer Student: She transfers in at the beginning of October and gets lost in town before making it to school successfully. She never acquires the right school uniform either.
- No Sense of Direction: If you don't watch her like a hawk she'll wander off the moment you take your eyes off of her and get completely lost.
- Replacement Goldfish: Sakuya views Chihaya as one to extent. Though he scorns himself for it, its actually a positive example of the trope.
- Screw This, I'm Outta Here!: In her own route and Shizuru's route, she chooses to leave Gaia rather than keep fighting. In Akane's route, she presumably quits as well and Kotarou never sees her again.
- Super Strength: She's even stronger than Kotarou as a result of her contract with Sakuya.
- Transfer Student Uniforms: Justified - her new uniform turned up in the wrong size. In fact, it's Sakuya's size, because she thought he needed a uniform too.
- Tsundere: Chihaya is a fairly obvious tsundere, though this is mostly because Kotarou is pretty fond of teasing her and she's still not as blatant as Lucia. He catches on quickly in her route.
- Verbal Tic: Chihaya overuses desu and also pronounces it fully instead of the normal 'des' sound.
- You Gotta Have Blue Hair: Chihayas hair is bright orange.
Sakuya is Chihaya's bodyguard and butler. He is amazingly strong, fast, Bishōnen and durable. On top of this, he is excellent at essentially everything. Unfortunately for Kotarou, he seems to have gotten on Sakuya's bad side almost immediately and thus has to endure a constant rain of insulting nicknames.
- The Ace: Sakuya is amazing at essentially everything.
- Attack of the 50-Foot Whatever: In Chihaya's route and the Moon route, he takes on an alternate form larger than any other familiar in the story.
- Battle Butler: He's officially Chihaya's butler, though he tries to claim at first that he's her brother. Personally, he refers to himself as her knight, which shows his sheer resolve to protect her no matter what.
- Bishie Sparkle: When asked to go outside the clubroom, he wanders the hallways being gorgeous and charming, making many girls quickly fall for his bishie sparkles.
- Bishōnen: Kotarou irritably notes that with Sakuya's looks and personality he would be very popular.
- Blank White Eyes: Complete with black screen and cold wind whenever Chihaya makes a comment that hurts him.
- The Cavalry: In Moon Route Sakuya shows up after Lucia, Kotori, Sakuya HB, Akane and all the normal people Kotarou called for have fallen. His presence alone is enough to help turn the tide of battle for the moment.
- Cherry Blossom Girl: Gender-inverted. His name even sounds like Sakura, and as a man who transformed into a cherry tree, and then reborn as a familiar, the affiliation is fairly explicit.
- Chick Magnet: Whenever he walks the halls, crowds of fangirls gather to gush over him.
- Cloth Fu: His secondary ability and the one that differentiates him from Kotarou, who instead has body fluid control/Aurora is the ability to manipulate cloth.
- Failure Knight: Sakuya protects Chihaya because he failed to protect the woman he loved from Salvation.
- The Gadfly: He claims to hate Kotarou and constantly screws with him, but mostly just seems to enjoy teasing him.
- Generation Xerox: Kotarou is this to him in the Chihaya Route.
- It is even more true in the Shizuru route, in which Kotarou also fails to stop Salvation, and becomes a tree.
- Heroic Sacrifice:
- In Chihayas route, Sakuya sacrifices himself to save Chihaya, Kotarou and Akane. However, Akane takes his body and turns it into a giant monster. Hes returned to normal, but this doesnt save him.
- In Moon Route, he comes to the aid of the group by fusing all of his potential existences together. It does get him to the battle, but at the cost of sacrificing himself from ever existing in any recreated world.
- Hypocritical Humor: Sakuya criticizes Kotarou for openly thinking the miso soup Chihaya made was terrible, but similarly collapses himself moments later.
- I Hate Past Me: In a manner of speaking. Sakuya refers to and thinks of Kotarou as his past self, though they're entirely different individuals. Because of this, he is somewhat ashamed to see Kotarou and treats him quite hostilely.
- My Greatest Failure: Sakuya was unable to protect his love Minata.
- Parental Substitute: Sakuya largely serves as Chihayas father figure, though hed prefer to be thought of as her big brother.
- Plant Person: Since becoming a familiar.
- Really 700 Years Old: Sakuya is from a previously wiped out civilization of an unknown age. Shizuru's route mentions seventy thousand year old civilizations and Moon route implies that there are many much older than that that. That said, he spent most of that time as a tree. When the tree starts dying, Sakuya goes with it.
- Red Eyes, Take Warning: Sakuyas eyes are a pretty good hint that theres more to the guy than just some goofy guy that makes fun of Kotarou.
- Ret Gone: His death in Moon Route wiped his existence from all future possible worlds. He somehow managed to appear one last time in Terra route.
- Spotlight-Stealing Squad: Chihaya's route is actually at least as much about Sakuya as Chihaya herself if not more.
- Tall, Dark, and Handsome
- Tsundere: A rare, non-romantic example. In her route, Chihaya mentions that Sakuya doesn't actually hate Kotarou nearly as much as he pretends to.
- Why Did It Have to Be Snakes?: Sakuya is so afraid of cats that he completely freezes up.
She is the Key that Gaia and Guardian are seeking - a kind of familiar produced by the Earth.
- A-Cup Angst: In the Oppai Ending, she reveals that she has chest size issues.
- Apocalypse Maiden: The Key is here to observe mankind and see if they the world should be saved.
- Breaking the Fourth Wall: In the Oppai Ending, she laments how few lines she has compared to the other heroines.
- Cute Mute: In several routes, she's barely capable of speech. She's capable of learning to speak any human language very quickly, but is frequently kept from learning anything since being in the outside world puts her in danger of being discovered.
- Defrosting Ice Queen: She starts showing more emotions when she interacts more with Kotarou.
- Elegant Gothic Lolita: She wears a black gothic lolita style dress.
- Emotionless Girl: During most routes she is very inexpressive and inhuman, so she kind of creeps Kotarou out on the few occasions he sees her.
- Good All Along: She doesn't want to cause Salvation, but it's not something she can control. She's trying to find a perfect solution that allows humanity to survive but can't find one.
- Good Is Not Nice: Despite trying to save humanity, Kagari is kind of an impatient jerk. She can also be pretty callous.
- Hair Decorations: She wears a cross-shaped hair clip on both sides of her hair.
- Improbable Weapon User: She has long red ribbons attached to her wrists that act upon her will.
- Invisible to Normals: The Key cannot be seen by most people. Its not that shes invisible, but people just sort of overlook her. She places a lot of faith in this ability which is generally how she gets found: She doesn't take proper precautions to hide normally and just assumes that if no one can see her it's okay to leave plenty of evidence about where she is.
- Lack of Empathy: She's born as a basically Blank Slate that is here to judge humanity and see if they can coexist properly with the Earth and at the beginning has no real intellect or emotion. After developing intellect, she still has nothing like human emotion or empathy. In some routes, she has no real humanity or emotion. In Terra he learns that she really does want to save humanity, but she's brutally pragmatic and wishes to kill Akane even though she's not even capable of speech or telling anyone that she saw Kagari. Kotarou is appalled though he agrees that she might be right.
- MacGuffin Super Person: She is the Key that two secret societies, Guardian and Gaia, are fighting to secure.
- Murder Is the Best Solution: Her idea of problem solving in Moon seems to always involve 'kill the annoyance' and in Terra she always urges Kotarou to hurry up and massacre Gaia and Guardian or to take over the world.
- Mystical Waif: She looks like a little girl and wanders around investigating the planet and humanity, but is in fact the Key that can trigger the apocalypse.
- Mystical White Hair: Her white hair isn't commented upon, but she's a clearly inhuman entity with great power and ability.
- Only One Name: She's only known as the Key or Kagari and the latter isn't quite her name either. She gets a last name in Harvest Festa, though.
- Perception Filter: Only a few humans can actually see her. Familiars are better at it, though. Everyone else just sort of tunes her out.
- Purple Eyes: She has deep lavender-coloured eyes, another sign of her inhuman nature.
- Rei Ayanami Expy: Silver hair with pale skin? Check. Mysterious and unsettling emotionless demeanor? Check. Inhuman entity with great power? Check. Shows more emotions thanks to the main character? Check.
- Starfish Language: In Moon route, she speaks in a highly advanced way that it appear as "■ ■ ■ ■ ■". Kotarou's head hurts just from hearing it. Kagari is also not really her name but implied to be a description of what she is, but she cannot state that any more clearly than the word 'Kagari.'
- Third-Person Person: She uses the third person in Terra, the first route where she really begins to speak. It's not quite cute so much as viewing herself as something that fulfills a role rather than an individual.
- Trademark Favorite Food: The first way Kotarou manages to get through to her in Moon is by sharing coffee with her. After her initial disinterest, she seems to grow pretty fond of it.
- Uncanny Valley Girl: The Key in Kotori and Shizurus route is highly alien and doesnt really feel like a human. In Kotoris route it can barely speak or do anything that Kotarou is capable of interpreting easily. In Shizurus its more talkative, but still incapable of interacting with him in a way he can appreciate. She's closer to this in her own route (in the anime and the upcoming Plus expansion) and in Harvest festa!, where she joins the school as a regular student and tries to be popular, but is just a little weird. All right, a lot.
Nishikujou is a rather ditzy looking teacher that commands a lot of respect at Kotarou's school, though she's new to the job. She has close ties to Shizuru and Lucia due to her work with the group Guardian.
- Conflict Ball: In Chihaya's route she expresses a severe hatred for familiars so the story can have her pick a fight with Sakuya despite both he and Chihaya retiring from Gaia. There is no real reason given and it contrasts her normal rather easy going or at worst strictly professional attitude.
- Curtains Match the Window: She has purple eyes and hair, though you rarely see her eyes.
- Cuteness Proximity: She can't resist trying to hug Shizuru.
- Drives Like Crazy: Invoked and averted. Kotarou expected her to drive like a maniac, but the worst she does is sing along badly to music from the 80s.
- Explosive Overclocking: When Nishikujou starts going all out with her ability, it begins tearing up her body.
- Eyes Always Shut: She tends to keep her eyes shut because they're rather sharp and scary looking. Since being a teacher is her dream job, she finds this pretty disheartening.Kotarou: Sensei, you're scary with your eyes open...
- Forgotten First Meeting: She was Kotarou's comrade and friend during his first training period in Guardian.
- Flechette Storm: She can fire off a large number of knives at once (particularly evident in Shizuru's route), resulting in this.
- Go Out with a Smile: In Shizuru's route she launches herself as a projectile at Kagari, smiling as she does so. It doesn't work.
- Hot for Student: She makes some flirty remarks towards Kotarou from time to time, but she's probably just being silly.
- Hot Teacher: Her looks appear to be one of the reasons she's so popular, but she dances around the question of her age.
- Japanese Christian: In the Terra route it's noted that, despite her Japanese name, she's in the faction of Guardian associated with the Catholic Church.
- Knife Nut: She uses her ability to make knives follow a target, though she's not limited to them.
- One of the Kids: She acts goofy and laid back when she's not required to be serious and ends up feeling less mature than Shizuru.
- Parental Substitute: Lucia was assigned to her command because psychologists felt she needed to be around someone motherly.
- Sensei-chan: She's a really ditzy, happy go lucky teacher and gets along really well with Shizuru in particular. She isn't really a teacher, though, but she wants to be one.
- Senseless Sacrifice: In Shizuru's route, she throws everything she has at Kagari, up to and including turning herself into a projectile. Kagari survives and still ends the world.
- You Gotta Have Blue Hair: Her hair is a bright purple color.
Arata Imamiya is a playboy who dresses young for his age. He is a member of Guardian.
- Handsome Lech: He seems to like the image of a flirty young guy, though he hints that he tries not to form close relationships.
- Jerk Jock: When he was younger, he was kind of an arrogant jerk. For the most part, he grows out of it by the time Rewrite begins.
The middle-aged owner of an antiques shop; he frequents Gen-san's ramen stand. He is a retired Guardian operative.
- Bad Liar: When providing a cover story for why he was in the forest chopping up monsters, he says he's a scientist investigating UMAs. He also claims to be a birdwatcher and Kotarou asks him if he's seem any dodo or moa lately. He says yes and that he owned a cute little moa himself. Granted, Esaka was not really concerned about actually convincing Kotarou and was possibly trying to make him more interested.
- Boke and Tsukkomi Routine: He's always very serious, but he seems to be very fond of playing both the boke and tsukkomi. Unfortunately, nobody has any idea what he's doing. In Terra, someone in Guardian even thinks they're under attack when he's trying to be humorous and thanks Kotarou for 'saving' him when he performs the tsukkomi Esaka requested beforehand.
- Cannot Tell a Joke: He thinks he's good at comedy, but he actually just terrifies everyone when he tries doing a Boke and Tsukkomi Routine.
- Catchphrase: "WHYYYYYYYYYYY!!"
- Cool Old Guy: He's a nice, professional old guy and one of the most powerful characters in the story. He also served as Kotarou's mentor and recruited him into Guardian once.
- Fights Like a Normal: He's a powerful superhuman, but of the three general categories of ability, his is the least flashy. Thus, he just fights with a sword.
- Forgotten First Meeting: In the past, he was the person who first introduced Kotarou to Guardian.
- Katanas Are Just Better: Thanks to his ability and sheer skill, he can use a simple sword to become an amazing physical combatant. Of course, he's kind of cheating when it comes to cutting through just about anything rather than his sword being that great.
- Large Ham: Even his character portrait leaps out at you whenever he's being hammy.
- Mentor Archetype: He is the person who brought Kotarou into Guardian.
- Retired Badass: He's in a state of semi retirement now, though he's considered perhaps the most powerful superhuman at Guardian's disposal.
- Shopkeeper: He's the owner of an antiques shop.
- What Kind of Lame Power Is Heart, Anyway?: Esaka confirms that he has an ability, but that its pretty useless. He doesnt want to talk about it. It turns out to be the ability to see the unseen. He lied. He possesses immense power to cut through things and lacks the ability he claimed to have.
- Worf Had the Flu: In Shizuru's route Sakuya quickly beats him before Kotarou and Shizuru can arrive as backup, but this is because he was caught off guard. We don't see him fight until Terra.
The owner of a ramen shop just off the main park in Kazamatsuri. He is a retired Guardian operative.
A mad scientist who, attempting to create someone who could survive the apocalypse, created Asahi Haruka.
The current leader of the Martel Group. Also the Holy Woman of Gaia, the most powerful member of the organization. She hates humanity with a passion, and is an extremely skilled summoner. She is Akane's adoptive mother.
- Adaptational Attractiveness: In the anime adaptation of Terra route, she looks like a particularly attractive forty-year-old despite being over seventy. Not so in the Moon and anime-original Kagari arcs, where she just looks old.
- Big Bad: She's the leader of Gaia, the darker of the two warring groups.
- Evil Old Folks: Sakura is over seventy in Terra and over eighty in the other routes, and she's the game's Big Bad.
- Full-Name Basis: Most of the characters will only refer to her as "Kashima Sakura."
- Go Mad from the Revelation: She's intelligent enough to be levels above all of humanity in how much she knows, thus realizing that life is empty and love is a lie, but she doesn't know that even higher above that is the fact that love is really responsible for everything. Thus, she's determined to end all possibility of life. In the process of discovering this, her ability as the Holy Woman partially broke.
- The Man Behind the Curtain: Despite being the most powerful summoner, she is physically old and frail. In Terra route, she dies before Kotarou could confront her.
- Omnicidal Maniac: She wants to end all life permanently and stop Kagari from saving humanity.
- Transferable Memory: The Holy Woman transfers her memory to a successor when she dies. She might be the last proper Holy Woman because her revelation into the true nature of the world is hinted to have damaged this ability in some manner.
Voiced by Hikaru YukariA member of the Martel group. He is also a member of Gaia, and plays an important part in Akane's route, where it is revealed that he used to serve Sakura Kashima in the same capacity that Kotarou now serves Akane.
- Ambition Is Evil: Subverted. When Kotarou says that he thought Suzaki was just power hungry, Suzaki says that he needed more power in order to save the world.
- Hero Antagonist: To Kotarou's (admittedly, unwitting) Villain Protagonist in the Akane route.
- The Starscream: He's been attempting to sideline Sakura Kashima and the religious cult side of Gaia for years in favor of a political extortion scheme. He doesn't care much about the Key's role in Salvation. They're too destructive and crazy for him. If Suzaki is taken out, the Holy Woman will attempt to end the world immediately.
- Well-Intentioned Extremist: His plan to commercialize familiars in order to save humanity as a whole is actually a lot more reasonable than Kashima and Akane's plans to bring about salvation and destroy humanity. Furthermore, in Terra Route, this is basically half of the plan used to save the world.
A member of the Martel Group. He's a member of Gaia and works with Suzaki's faction and appears in the Akane route.
- Ax-Crazy: Has gone completely insane by the time he reappears after the one year timeskip in Akane's route.
- Berserk Button: His ears apparently resemble Gyoza. He does not like it when people point this out.
- Body Horror: After Kotarou slashes him to ribbons in the forest, he turns his decomposing body parts into familiars as he dies, by using the energy from the toxins that seeped into his body from his environment. By the time he reappears after the timeskip, he's constantly shooting himself up with drugs in order to continue providing himself with energy to maintain his familiars. It's mentioned that his human body parts are still being slowly poisoned while he's doing this.
- Catchphrase: "HAAAAAPPPPPYYYYYYYYYYY!"
- Green-Eyed Monster: To Kotarou.
- Mugging the Monster: On Kotarou, pre-timeskip. It doesn't end well for him.
- Unwitting Instigator of Doom: He poisons Sakura Kashima, causing Akane to become the new Holy Woman and gain the obsession with ending the world. Akane ends up destroying the world with a replicated Song of Salvation.
The Earth Dragon
One of Gaia's oldest and most powerful familiars, the Earth Dragon was created from the corpse of an ancient Tyrannosaurus Rex. Due to its extremely long existence, it has developed sentience and a soul of its own. It views the Summoners of Gaia as its children.
- Awesome, but Impractical: Despite its great power, the Earth Dragon is also very inefficient in battle, and as such, even empowering it for a short period for time requires the lives of dozens of summoners. Akane also notes that because it is so large, it is impractical for use in urban areas, and as such, can only be brought out on a few occasions.
- Curb-Stomp Battle: Everytime it fights someone other than Kotarou.
- The Dreaded: Kotarou's reaction when he first runs into it during the Terra route. His hiding is completely understandable due to the dragon's immense size, and that it kills Mikuni and his team, who were the top ranking students in their class, while Kotarou finished near the bottom.
- Friendly Enemy: The Earth Dragon is actually a pretty cool guy once you get to know him.
- Hero Killer: Towards Guardian members at least, due to the dragon being affiliated with Gaia. This is certainly how Kotarou first viewed it when he was starting out in Guardian.
- Instant Awesome: Just Add Dragons!
- Lightning Bruiser: It's actually very fast and very agile despite its massive size.
- Punch-Clock Villain: He shows great respect towards people that it views as Worthy Opponents, and actually takes some time to speak with Kotarou and allows him to prepare before its fight with him in the Terra Route. Earlier in the route it spared Imamiya because it was just taking a walk at the time and wasn't interested in fighting. It merely fights because it is expected to do so and feels it should honor the efforts of the summoners who awaken it.
She works for Akane as her secretary, and is also a summoner of Gaia.
- Discard and Draw: She lost her abilities as a superhuman, and instead gained the ability to control familiars.
- Forgotten First Meeting: She and Kotarou used to be squadmates when she used her original name of Nagai. She quit and he was injured so badly that he was retired. Neither remembers the other.
- Sexy Secretary: Apparently she's quite pretty, though we have to take Kotarou's word for it.
Midou, Tenma, and Tenjin
Rogue summoners of Gaia who each control a powerful familiar.
- Death Seeker: All of them, although given a choice they would like to take down everyone else with them.
- Giant Flyer: Tenjin's familiar, Kilimanjaro
- Hot-Blooded: Midou
- Jerkass Woobie: Each has a horrifically violent past.
- Not So Different: Midou thinks this of Koutarou
- Playing with Fire: Midou and his lava familiar, Fuego.
- Omnicidal Maniac: Their goal is to destroy the world.
- Self-Disposing Villain: Tenma is killed after his own familiar, Krivoy Rog, drains too much of his own life-span in an attempt to regenerate the wounds inflicted by Sakuya.
ShimakoA seven-year old disciple of Gaia who appears in the Akane route.
- Child Prodigy: Has incredible talent as a summoner.
- Creepy Child: As a very young girl, she almost never moved, using her powers to control objects around her instead, which freaked out her parents.
Kotarou's classmate, a rough-talking self-styled delinquent.
- Butt-Monkey: Kotarou really has to work at it to make him into the butt of jokes though. And unlike his earlier Key predecessors it sometimes backfires on him.
- Forgotten First Meeting: Terra reveals that he met Kotarou when he was an elementary student after Kotarou saved him from some bullies, though he goes unnamed apart from script files. Yoshino began hero worshiping him, so Kotarou randomly chose to give him advice like being a momma's boy and a diligent student. Though he seems disappointed, you can see that in the present he follows the advice quite thoroughly.
- Graceful Loser: At the end of Kotori's route, Kotarou finally fights him seriously and utterly flattens him. After his honorable defeat, Yoshino gives his blessing to the two.
- Hopeless Suitor: It's implied throughout the story that he likes Kotori, but the two barely even talk. He knows he doesn't have a chance as well.
- Jerk with a Heart of Gold: He's much nicer than he initially lets on, as evidenced by how easily he's roped into the Occult Club's latest zany schemes. He seems to suffer if anyone notices this though.
- Large Ham: Played for Laughs. He talks like a shonen manga protagonist. Kotarou constantly mocks him for this tendency.
- Malicious Misnaming: When Kotarou introduces Shizuru to him, he has three different options of weird ways to do so. Shizuru sticks to calling him things like Giraffe every time they meet after that.
- Momma's Boy: When in his own home he drops his normal demeanor entirely and acts like a complete dork, much to Kotarou and Kotori's amusement.
- The Rival: Yoshino keeps wanting to fight Kotarou seriously. At first it seems that Kotarou runs away from the fights to avoid getting beaten up, but its actually the opposite. In Moon, Kotarou says he is grateful than Yoshino was his rival and not his friend because that meant he could never really relax. His final conversation with Kotarou in the story is the two finally calling each other by their first names.
- Vitriolic Best Buds: Kotarou pretends that he and Yoshino are best buddies, but Yoshino really is pretty pissed off with how Kotarou behaves and with how he secretly doesn't care about the people he acts friendly towards. They are friends to an extent, though.
The resident School Newspaper News Hound, who takes an interest in the club's investigations into the occult.
- Ascended Extra: She didn't even have a sprite until Harvest Festa.
- The Cuckoolander Was Right: Inoue is suspicious of people like Akane and Kotarou and her suspicions are right on target. Akane is the adopted daughter of a cult leader and Kotarou shouldn't be in school at all anymore at his actual age.
- Eat the Evidence: Kotori's route reveals she swallowed her own memory stick to hide her exploration log of the Gray City.
- Intrepid Reporter: She snoops around school at night and even in the forest to look for news.
- Laser-Guided Amnesia: Her memories were erased when she got caught in the Gray City.
- The Rival: She sees herself as a rival to Kotarou. It's implied that this developed into a low grade infatuation.
Pani and Gil
Pani and Gil are two strange creatures that Kotarou finds in the strange alternate Kazamatsuri. He's not sure what they are, but since they seem harmless he lets them stay at his place.
- Big Eater: The amount Gil eats isnt that large until you consider his body size. That much food shouldnt fit inside him. Even he doesnt understand it.
- Buttmonkey: Gil tends to take a lot of abuse because of his arrogance.
- Genetic Memory: They remember things from before they were born such as the experiment Gaia performed that brought their predecessor into being years before they were born. They appear to be a fusion of that creature's remains and scientists that it killed and thus has their memories.
- Hopeless Suitor: Pani seems to have a crush on Kotarou but he mentally classifies her as 'Weird Thing' rather than 'girl.' Not that it's important.
- Jerk with a Heart of Gold: Gil.
- Megaton Punch: Pani punches Gil as hard as she can pretty frequently.
- No Biological Sex: According to Pani, she and Gil have no sexual organs and cant reproduce.
- Ojou Ringlets: It's not really possible for Pani to be actual royalty or anything, but she looks, acts and dresses the part.
- Shoo Out the Clowns: Pani and Gil are not invited into Moon route and Kotarou says he would feel ridiculous if he asked them for help. They probably don't exist yet in Terra either. A reader who knows much about who wrote each scenario might notice that they only appear in routes written by one of the three authors.
- Super-Deformed: They're very chibified in appearance. They have tiny bodies and massive heads with gigantic eyes.
- You Gotta Have Blue Hair: Pani's hair is pink.
A young girl who appears during Lucia's route. She's slightly insane and believes that the world has never liked her. Around seven years ago, a transfer student who came from the same orphanage as her caused an uproar when he suddenly died the next day, which was attributed to him having met Asahi Haruka. Initially, the investigation into her was to dispel rumors, but eventually it shifts into Kotarou trying to clear her name when he realizes that if the story were true, then Haruka never actually did anything wrong.
- The Dreaded: Everyone who knows of her story is terrified of her curse. Glass will break around them, they'll see a mysterious girl and potentially fatal accidents will occur around them until they stop. One particularly persistent investigator ran into her and got a purple bruise mark that won't heal for his troubles.
- Foil: The intention of her character is to be like Lucia so that she can set up her route. The twist is that she is actually Lucia.
- Incoming Ham: Her introductions are always over-the-top, and they are always introduced with her iconic lights breaking.
- Psychic Powers: From making glasses scratch and break, to tilting a restaurant sign.
- Touch of Death: When she came in contact with several people, they all died under mysterious circumstances. Four years ago, an investigator was threatened when a restaurant sign fell close enough to kill him. It was also rumored that she killed off everyone in the orphanage.
- Troll: During the investigation, it seems like Haruka is taunting people to make them suffer and therefore go away and leave her alone.