- Action Dress Rip: Saya rips off part of her school skirt and turns it into an Eyepatch of Power in episode 12.
- Action Girl: Any scene of her fighting the Elder Bairns can tell you this.
- Adorkable: Oh, is she ever!
- Aloof Dark-Haired Girl: Her true personality fits this to a T.
- Anti Heroine: Becomes one by episode 12.
- Badass Adorable: Despite going on missions to kill monsters she's an otherwise sweet and charming young high school girl. Though this fades once she gets her memories back.
- Barbie Doll Anatomy: Close-up during the OP.
- Boobs of Steel: Sports quite the rack and is the only half-human female who's capable of fighting.
- Break the Cutie: Let's just say the second half is not very kind to her.
- Broken Bird: In Blood-C: The Last Dark.
- Chaste Heroine: Other than some implied interest in one of her classmates, she has no romantic relationships.
- Chronic Hero Syndrome: In the first episode, her classmates say she is usually late for school because she goes to help lost children and grandmas and pick up trash.
- Cool Sword: Her mother's sword.
- Crouching Moron, Hidden Badass: For much of the series, she comes across as being completely inept at saving people from the monsters. Then you find out it's because she subconsciously doesn't care but could, in a heartbeat, if she truly felt like it.
- Cute Clumsy Girl: Acts frequently air-headed and keeps falling face first while running. Though it's not a part of her true personality.
- Cuteness Proximity: Whenever she sees the dog she feels the need to stop and pet him.
- Daddy's Girl: She's very close to her fake father.
- Eye Scream: Aside of, you know, having half her head blown off by Fumito.
- Failure Heroine: Taken to a gruesome extreme.
- Fake Memories: Most everything Saya remembers that isn't from a flashback is fake.
- Freakiness Shame: Implied. In the anime, she flinches and looks absolutely heartbroken when Tokizana calls her a monster. In the Movie, one of Fumito's soldiers calls her a freak, to which she responds with a very charged "Shut up!"
- Girlish Pigtails
- Girl Next Door: To Fumito.
- Good Eyes, Evil Eyes: She usually has Tareme Eyes, but in her Let's Get Dangerous! moments they become Tsurime Eyes.
- Gray Eyes: Unless she's kicking a vampire's ass.
- Hidden Depths: Despite her established klutziness, Saya is REALLY good at sports.
- Humanoid Abomination: She's actually half Elder Bairn.
- Hunter Of Her Own Kind: Subverted; she does not hunt her own kind for any honorable, heroic or moral reasons.The only reason that she hunts them at all is only due to an unknown pact made long ago that forbids her from killing or devouring humans. If she could, she would have no quarrel with her kind.
- Laser-Guided Amnesia: As part of her "game" with Fumito.
- Late for School: Usually because she sees a puppy she wants to pet...
- Magic Skirt: Tossed, flying through the air, feet first.
- Miko: Obviously, being the town's local shrine maiden.
- Missing Mom: Her mother died when she was a child. Or so she thinks.
- Nice Girl: Saya is a bright, cheerful, kind, and all friendly person to everyone and everything around her. However, It is later revealed that she is far from this.
- Nominal Heroine: In Blood-C: The Last Dark (and quite possibly the show itself); Saya only sides with SIRRUT to further her quest for vengeance against Fumito.
- Not So Stoic: Whenever Fumito is involved Saya completely looses her cool and fly's into an uncontrollable, homicidal rage.
- Oblivious to Love: As the twins point out, she really can't tell when a guy is interested in her.
- Raven Hair, Ivory Skin: Has the qualities and is noted to be quite attractive. In fact, once she's revealed to be part Elder Bairn, her teacher comments on her inhuman beauty.
- Red Eyes, Take Warning: Usually means she's going to kick some ass or drink blood.
- Single Woman Seeks Good Man: She "loves" Fumito because he's a Nice Guy.
- The Stoic: When she learns of the Truman Show Plot.
- Survival Mantra: In the first episodeSaya: Ikutama, Tarutama, Tamatamarutama. Amenotokotachi no Mikoto, Kuninotokotachi no Mikoto. note
- This is an actual Shinto prayer.
Voiced by: Keiji Fujiwara (Japanese), Bill Jenkins (English), Alfonso Vallés (Spanish)Saya's father and the priest at the shrine where he and Saya reside.
- Birds of a Feather: Non romantic example. His half human nature made him sympathize and get along with Saya.
- Brainwashed and Crazy: While under the influence of Saya's blood during their fight in episode 12.
- Half-Human Hybrid: Half-Elder Bairn, just like Saya.
- Panthera Awesome: His One-Winged Angel form looks something out of ThunderCats (1985).
- The Stoic: His personality; he shows little to no emotion.
- Ambiguously Human: His eyes flash red just like Saya's in the third trailer of the movie The Last Dark, and, appropriately, he is revealed to have tried to become a half-Elder Bairn like her.
- Big Bad: He set up the entire town as part of a "game" with Saya.
- Bastard in Sheep's Clothing That nice cafe owner is a royal douchebag.
- Dissonant Serenity: Not matter what happens around Saya, he is always serene and kind. Not even when he drops his facade.
- Driven to Suicide: Stabs himself with Saya's sword since he found that he is incapable of being the same as Saya and that his attempts of making new Elder Bairns failed.
- Expy: Of Solomon Goldsmith from Blood+, both in looks and personality. Much like Goldsmith, Fumito acts out of love for Saya, and is also inhuman.
- Human Resources: His goal is to create Elder Bairns from humans so that Saya, who refuses to feast on humans and instead feasts in her own kind, would never run out of her food supply.
- Love Makes You Evil: Everything he did was for Saya, even if it was because his own obsessive love for her.
- Manipulative Bastard: Was responsible for everything involving the experiment on Saya.
- Nice Guy: Or so he seems.
- No Body Left Behind: His body turns to ash after he stabs himself with Saya's sword.
- Self-Made Orphan: Kills both his and his cousin's family.
- Transhuman: He tried to become a being like Saya in order to be with her, but he failed.
- Walking Spoiler: The biggest one in a cast full of them.
- Yandere: For Saya.
Nono and Nene Motoe
- Bitch in Sheep's Clothing: Implied pimps, and complete jerks.
- Creepy Twins: After dropping the facade.
- Eviler Than Thou: While both are bad, Nono is much worse than Nene, first willingly letting herself be possessed by an Elder Bairn in order to slaughter people and fake her death, then later betrays Nene and leaves her to die in order to save herself.
- Genki Girl: Both of them are highly energetic. This is actually not an act, and part of their real personalities.
- Half the Man He Used to Be: Nono gets caught by an Elder Bairn, held upside down via her legs and split apart like a wishbone
- Identical Twin ID Tag: The braid in their hair is the only way to tell them apart - Nene's is on the right side of her face and Nono's is on the left.
- Metronomic Man Mashing: Nene gets smashed into a pulp on the pavement. Almost a mercy kill in comparison to her sister's fate...
- Karmic Death: Could be said for Nono, as she knocks Nene to the ground to try to save her own hide. While they both die, her death is more drawn out and painful, whereas Nene dies the fastest out of anyone there. Also there's the fact that Nono is torn in half...a fitting punishment for betraying Nene, her other "half".
- Noodle Incident: We learn that they did something REAL bad in the past and they were jailed for it. We get a clue in episode 12 when they say that the fake uniforms are cute and that they should get a bunch for "the girls" to wear. This suggests they were pimping out a bunch of girls and got caught for it.
- Single-Minded Twins: They frequently do this but it's mostly an act.
- Synchronization: Often speak in unison.
- Theme Twin Naming: Their names are basically the same, you just have to interchange the Os with Es or vice versa. Of course, it's not their real names.
- Trickster Twins: The Reveal paints them as this.
- Twincest: They seem about ready to kiss each other as a demonstration to Saya in episode 2.
- With Friends Like These...: Turns out that in Episode 12, Nono's love for Nene was not as genuine as it seemed seeing as she easily elbows her own twin in the face to the ground and uses her as bait in an attempt to escape from Cerberus to save her own skin. It doesn't work.
- You Have Outlived Your Usefulness: Trying to cross the boss gets them this treatment.
Voiced by: Masumi Asano (Japanese), Martha Harms (English), Ariadna Jiménez (Spanish)A mature classmate of Saya's who often has lunch with her.
- Karma Houdini: Never receives any punishment for her involvement with the Truman Show Plot, and even becomes Governor of Tokyo during Blood-C: The Last Dark.
- Older Than She Looks: She's 28 years old, to be exact, but can pass as a high school student.
- Sole Survivor: The only member of the group who wasn't dumb enough to betray Fumito, and not being a townie Red Shirt, is what keeps her from meeting the rest of the towns fate.
Voiced by: Atsushi Abe (Japanese), Chris Burnett (English), Carlos Lladó (Spanish)The class president. He has a crush on Saya.
- Becoming the Mask: He was told to pretend that he loved Saya... and fell in love for real.
- Class Representative: His role in the class.
- Dogged Nice Guy: To Saya.
- Dying Declaration of Love: To Saya.
- The Mole: According to Kuroto in Blood-C: The Last Dark, he was sent in as a spy.
- Sheep in Sheep's Clothing: The only decent participant in the Truman Show Plot.
- Taking the Bullet: The reason he died is that he took a mortal blow in Saya's place.
- Token Good Teammate: He's the only one of the "main cast" who's actually concerned about Saya.
Voiced by: Tatsuhisa Suzuki (Japanese), Scott Freeman (English), Dani Albiac (Spanish)A quiet classmate who harbors a secret interest in Saya.
- Bastard in Sheep's Clothing: Like everyone else around Saya, his behavior towards her is a complete facade.
- Decoy Protagonist: His aloof-nature, notable absences from school, and slowly building relationship with Saya (to the point where he is the first classmate to learn of her double life) make Tokizane out to be more important than he actually is. Even after the reveal of the entire cast being actors, we actually learn the least about him when compared to his cohorts.
- Off with His Head!: Thanks to a Giant Foot of Stomping from an Elder Bairn.
- Only in It for the Money: And his greedy nature bites him in the end.
- Tall, Dark and Handsome: Comes off as this all the time. But it's really just to attract Saya's attention.
- You Have Outlived Your Usefulness: Cue the beheading.
- You Monster!!: Straight up refers to Saya as a monster and a freak, and even goes so far as to say that she's one of the reasons he wants to leave the show so badly.
Voiced by: Miho Miyagawa (Japanese), Lydia Mackay (English), María Rosa Guillén (Spanish)Saya's homeroom teacher.
- Bitch in Sheep's Clothing: Is pretty quick to change personalities when she ends the experiment and treats Saya as nothing but a prize and research subject.
- For Science!: She only agreed to Fumito's "game" for the opportunity to experiment on people and Elder Bairnes.
- Hot Teacher: Boy, howdy...
- Psycho Lesbian: She appears to have a twisted attraction to Saya, outright groping her in episode 11.
- The Starscream: Willingly betrayed Fumito and gave Saya her memories back for her own ambition of exposing Saya to the world and making sure all the research and hard work she did wouldn't go to waste.
- You Have Outlived Your Usefulness: She managed to survive the Elder Bairn that Fumito had try to kill her, only to end up dying at the hands of Tadayoshi's Elder Bairn side.
- Shout-Out: The dog states he owns a shop where wishes are granted, hinting at the possibility of being Kimihiro Watanuki from CLAMP series ×××HOLiC (who Jun and Todd also voiced). This eventually becomes true in the movie.
- Talking Animal: He's a small dog who regularly converses with Saya. Subverted when it's revealed that he's simply a medium used by Watanuki to communicate.
The Elder Bairns (The Furukimono)
- Brainwashed and Crazy: Fumito had them imbued with Saya's blood and some special magic so he could control when they would attack.
- Eldritch Abomination: Are all incredibly inhuman and between needing to eat humans to survive and having existed for a very, very long time. They definitely count.
- I'm a Humanitarian: They must eat humans to survive. For this reason a covenant was made between them and man to ensure humanity wouldn't be wiped out.