Action Dress Rip: In the middle of a fight at the Metropolitan Opera House, Saya realizes that the evening gown she wore in is too restrictive and so takes the liberty of tearing most of the lower portion off for more ease of movement, leaving her legs pretty much bare.
Action Girl: Was one before the series begins, though she doesn't initially know it. She eventually gets back into the habit of kicking monster tail.
Amnesiac Dissonance: Starts out the series amnesiac, and slowly regains her memories over the course of the first two seasons.
Angsty Surviving Twin: Even after everything Diva has done, Saya still holds her and cries for her as she dies.
Animals Hate Her: Every animal she encounters over the series slinks away at the sight of her.
Big Eater: An instance of Fridge Brilliance: Saya only receives just enough blood to keep from getting thirsty, but her body still needs more energy. Human food isn't quite enough to match up to blood, which is why she burns through calories so quickly and has to eat so much.
Boomerang Bigot: Bears considerable disdain for most other chiropterans despite being one of them. See Took a Level in Jerkass below. It's probably justified considering most other chiropterans's disregard for human life and bloodthirstiness. Saya was raised to identify as a human. Other chiropterans kill humans without a second thought. Given that, it's only natural that Saya would cling to her alignment with humans and look at other chiropterans with disdain and distrust.
Boyish Short Hair: From at least the Russian Revolution onward. According to the Adagio manga, after having a nightmare of Diva's rampage at the Zoo and mistaking her reflection for Diva, she freaked out, messily chopped off her hair, and then had Haji fix it, resulting in its current style.
Broken Bird: Once she gets her memories back, she gets broken and bitter. Probably has something to do with three lifetimes's worth of bloodshed, fighting, monsters, evil global conspiracies led by her twisted twin sister who murdered her father-figure along with most of the people she knew and destroyed her home, having condemned Haji to a terrible, endless life as her chevalier, and struggling to cope with the knowledge that she herself is just another monster that caused all of this to happen and needs to die as soon as she kills her sister.
But Not Too Foreign: Sort of. She's technically French because of her place of "birth," but can easily pass for Japanese.
Death Seeker: Ultimately subverted. Saya only allows herself to live in order to kill Diva, and plans to either die with Diva or have Haji find a way to kill her afterward. Despite this, she secretly does want to live. In the final episode, Haji and Kai persuade her that she doesn't need to kill herself out of guilt or to end the chiropteran threat.
Drama-Preserving Handicap: As the series finale approaches, Cinq Fleches begins putting the Evil Plan into action, which includes transforming the human population into chiropterans and killing Saya to put an end to the threat she poses. Unfortunately, all this is happening at the same time that Saya's body begins preparing for its next thirty-year hibernation—meaning that she suffers from Power Degeneration that hinders her newly-regained fighting capabilities and might not even be able to confront Cinq Fleches in time before she goes to sleep. Awful, awful, awfully convenient timing.
Earn Your Happy Ending: She goes through over a century of physical and psychological pain, and has to endure thirty years of hibernation first, but she's finally able to live her life in peace.
Easily Forgiven: For her actions during the Vietnam War. Granted, she wasn't in her right mind at the time, but still, she killed dozens of innocent people, including women and children, chopped off Haji's arm, and personally slew David's father, and all she gets is a slap on the wrist. Almost makes the Red Shield seem like a bunch of hypocrites for giving her so much slack while they are convinced that Diva is an irredeemable monster. Again, justified by the circumstances: Saya is normally undyingly loyal to humanity, but was in a mindless frenzied state at the time (she didn't even recognize Haji) because she had been taken out of hibernation too soon and woke up in the middle of a war-zone crawling with chiropterans, bombs, and gun-fire. When Saya was herself again later on, she was horrified and remorseful over what she did in Vietnam, even before she consciously remembered it. The only reason the Red Shield continued to ally with Saya was because it was necessary, seeing as how her blood was the only weapon capable of killing the much more pressing threat—chiropterans in general and Diva and her chevaliers in particular. Still, the Red Shield was pretty wary around Saya at this time because they knew what had happened in Vietnam, and David had a hard time forgiving her even though he knew and accepted that Saya was necessary to their mission and that she hadn't been in control of herself in Vietnam.
It's All My Fault: Her word-for-word reaction when she remembers that she was the one who originally freed Diva.
Kiss of Life: Thrice with Hagi: the first time (chronologically), it was so that she could give him her blood to recuperate, accidentally turning him into a chevalier when he was on the brink of death but saving his life; the second time (chronologically), it was so that he could give her his blood to trigger her latent memories and powers, enabling her to kill an attacking chiropteran and save the day; the third time (chronologically), they share an emotional kiss after Haji convinces Saya not to kill herself.
Locked Out of the Loop: When she is recruited back into the Red Shield while amnesiac, both Haji and David repeatedly refuse to tell Saya anything about her past or mission, insisting that she has to remember on her own. Of course, this results in Saya being forced into horrific bloodshed and countless Break the Cutie moments without even knowing why, but either way...
Nice Job Breaking It, Hero: There surely could never be a reason why that girl with the beautiful voice is locked away in a tower on your foster father's property...
Oblivious to Love: She had no idea that Haji was in love with her throughout the past hundred-plus years of their association.
The Only One Allowed to Defeat You: Saya sees the task of killing Diva as her personal duty, and tries to dissuade others from joining her in her quest. This isn't just a matter of It's Personal as it usually is with other examples (though considering the grief Diva has caused her, that certainly figures into it as well), but out of pragmatism and a sense of responsibility—Saya's blood is the only thing that can kill Diva.
Out, Damned Spot!: During the Vietnamese boarding school arc, Saya is washing her hands when she hallucinates that they are covered in blood, symbolizing her subconscious guilt over all the innocent blood she spilled in Vietnam the last time she was there.
Power Degeneration: A non-fatal variation. As Saya nears her next hibernation period, she suffers from bouts of fainting spells and her Healing Factor begins to lose its potency.
The Promise: She made Hagi promise her that he would kill her after she kills Diva. Fortunately, he instead manages to talk her out of it and persuade her to live on.
Sympathy for the Devil: Despite her long-running mission to kill Diva, Saya still feels sorry for her due to her Freudian Excuse. When she finally succeeds at killing her, she considers it a hollow victory and breaks down in tears.
Knife Nut: Seemingly able produce an endless supply of throwing knives out of nowhere.
Living Forever Is Awesome: Haji is proof that this trope is not for loners; he appreciates his immortality because without it he couldn't serve his mistress when she's awake or watch over her when she hibernates. Though one must wonder what he does during the latter.
Undying Loyalty: To Saya. Deconstructed as well, since in the finale, he would have just stood by and let Saya kill herself if Kai hadn't stepped in.
Willfully Weak: Suppresses a lot of his natural abilities because when Saya first saw him use them, she was terrified. He also basically starves himself of blood, which is why he is not as strong as the other chevalier, though if he tapped into his natural abilities and had enough blood, he would probably be second only to Amshel.
:Dude, She's Like in a Coma: A gender inverted example. After David saves her from getting shot by Collins, literally Taking the Bullet in the process, Julia kisses an unconscious David after he gets out of surgery.
Face-Heel Turn: She is convinced by Collins to defect to Diva's side along with him...
Ambition Is Evil: The whole reason he betrayed the Red Shield for Diva's group in the first place is because he wanted to make his research on chiropterans public, which the Red Shield forbade him from doing.
Armor-Piercing Slap: Delivers one to Saya after discovering that Saya's next hibernation period is coming and Saya didn't think it important to tell anyone.
Demoted to Extra: Only appears as a very minor character in the manga, first bullying Saya because she's jealous that she lives with Kai, then recruits Saya to be in the school play in hopes that Kai will come and watch.
Spoiled Sweet: She's remarkably nice considering her dad's status and wealth
Stalker with a Crush: Mao steals four million yen from her mob boss father's untraceable cash stash to follow Kai across the world.
Tsundere: Dere for Kai, tsun for everyone else, especially Okamura.
What the Hell, Hero?: Along with the Armor-Piercing Slap moment mentioned above, Mao also chews Saya out for not bothering to tell anyone her next hibernation cycle is approaching when they've been working their butts off to help her.
Yakuza Princess: Her dad's a mob boss and she certainly carries herself like a princess.
Alas, Poor Villain: An in-universe example. Saya starts bawling her eyes out after killing her.
All Women Love Shoes: Rare anime example. She sees a guy with cute sneakers, kills him, takes said shoes and wore them for the rest of the episode.
Anti-Villain: Diva is on par with Lucy herself when it comes to sympathetic anime villainesses: from the moment she was born, baby Diva was separated from her twin sister and locked up in a lonely cage at the top of a tower for decades, with her only human contact being men who saw her as nothing more than an experiment or an animal. All she ever wanted was to have a family, but she was denied even that, and died right on the cusp of realizing her dream. Diva's story is so saddening that it makes you want to give her a hug. Except then she'd bite your neck and suck you dry, at which point you'd remember that there's a reason why she's an Anti-Villain.
The Dreaded: Is this to the Red Shield to the extent that, when he meets her face-to-face, Lewis is so thoroughly intimidated by her that he falls back on his ass in fear, and is extremely relieved when she chooses to pursue Saya over eating him.
Go Out with a Smile: In both the anime and manga series. Anime-wise, the last thing Diva does before she dies is smile at the cocoons of her babies and caress them. In the manga, it's to give Saya a smile when the latter is about to commit suicide, and use her last breath to tell Saya to live.
Hoist by His Own Petard: Her rape and murder of Riku got her pregnant like she wanted, but the pregnancy sapped the poison out of her blood, thus disabling the only thing that could kill Saya. Therefore, when the sisters finally got their fight, Diva had absolutely nothing to kill Saya with and, after what Diva did to Riku (not to mention other people), Saya has every reason in the world to want her dead. It was only a matter of time before Saya succeeded in killing Diva.
A Million Is a Statistic: Quite a few people lost sympathy for Diva after she raped and killed Riku. Sure, never mind that she's filled entire graveyards over the past century. Even then, she won back some favor because of her love for her unborn babies... even though the way she expressed her motherly love was by planning to wipe the human race off the face of the Earth for them.
Motive Rant: Gives one to Saya right before they fight at the opera house, in the hopes that her sister would agree and they wouldn't have to kill each other.
Muscles Are Meaningless: She is the exact same size and weight as Saya, but is shown to be powerful enough to punch David across a room and then toss Saya clean through a brick wall without even trying. As the other Chiropteran Queen, and a well fed one to boot this is justified.
Not So Different: She feels that she and Saya are the same, being not only chiropterans but also twin sisters. The similarities run even deeper than either of them realize: they both want to have a family, they both want to have a happy life, and they are determined to wipe out an entire race in order to preserve their own. At first, Saya vehemently argues against the idea that she is anything like Diva, but after killing Diva she rather solemnly acknowledges Diva as her "other half" in the original dub.
Pimped-Out Dress: Diva loves to dress up in beautiful dresses, the weirder, the better. Of particular note are the dress... thing she wears when she attacks Riku and destroys the Red Shield's headquarters that is just a frilly white cape clasped at the throat, with evening gloves and sneakers, and the black-and-blue gown she wears to her fight with Saya at the Metropolitan Opera House. Going by the latter's oufit's tiara and bat-like wings, it's supposed to show Diva's status as the queen of the chiropterans, but it just looks... odd. (Makes sense if Divadressesherself, though.)
Power Degeneration: Nathan explains that as a result of Diva's pregnancy, her blood lost its toxic property. She never realized this, since there was so little information on her species and none at all on what happened when queens became pregnant. When Diva faced off against Saya in their final duel, she effectively went into a gunfight with an unloaded gun.
Raven Hair, Ivory Skin: Black-haired, white-skinned Diva is described as "the most beautiful and dangerous woman" by one character. The crowning example of the series.
Roaring Rampage of Revenge: The very first thing that Diva does when Saya releases her from the tower is butcher Joel I and the patrons at his birthday party in retribution for all of the pain and suffering Joel put her through.
Ambition Is Evil: And how. Everything he does is because of his desire to find out everything he possibly can about chiropterans, and if that means overstepping all kinds of moral bounds and nearly causing The End of the World as We Know It, it's a small price to pay.
Bigger Bad: He's the one who turned Diva into the monster she is, and has spent the last century planning to convert humanity into chiropterans using Diva. He is the only one of Diva's chevaliers to outlive her... for a minute or two.
Creepy Crossdresser: First appears disguised as an old woman, then kills a Red Shield operative and spends the next few episodes disguised as her. And in the last few episodes, he arrives for the final battle disguised as Diva to buy time against Saya.
Curb-Stomp Battle: His initial battle with Saya in the present day. It ends with Amshel crushing Saya's arm and breaking her sword.
Harmless Electrocution: Averted. After being impaled on the Chrysler Building's spire, Amshel is fried by a lightning bolt attracted by the spire's point. He survives (barely) but his healing factor has him stuck between his human and chiropteran forms when he returns to finish his fight with Haji.
Taking You with Me: When Haji uses Saya's sword to kill him for good just before the MET is bombed, right before he completely crystallizes, he impales Haji with his claws and traps him, rendering him seemingly unable to escape the bombings.
The Medic: He used to be a military doctor before he turned into a chevalier.
Undying Loyalty: Towards Diva. He later feels this way towards Saya, to the point where he betrays Diva (though he still admits he cares about her.)
War Is Hell: His experiences during World War I was one of his main reasons to become a chevalier, so he could be free from seeing humans kill each other, only to discover that chiropterans are just as bad.
Worst Aid: After Saya pulls off a Deliberate Injury Gambit to kill Karl, Solomon stops her from pulling her katana out of her stomach, warning her that she could potentially damage her internal organs if she forces the blade out before quickly and cleanly yanking the sword out of Saya's body himself. If not for Saya's Healing Factor, she would have bled out right then and there.
Taking You with Me: In his and Saya's final fight, he has Saya at his mercy and attempts to completely drain her of blood, knowing this would kill him as well, so they could die together. Saya doesn't go for it.
Tragic Villain: Karl was made a chevalier against his will because Amshel wanted one to experiment on.
Commanding Coolness: As a high ranking Naval officer, he is responsible for Cinq Flèches military contracts and later the leader of the Corpse Corps.
Irony: After an encounter with Saya leaves him fatally wounded and unable to regenerate, he's forced to get Schiff implants to stay alive. This means Diva loses interest in him for the same reason he scorned the Schiff.
Mercy Kill: After seeing that Diva has died and lamenting on her own foolishness, he reverts to Chiropteran form and gently asks Saya to kill him, since he would essentially be living an empty life of immortality. Saya grants his last wish. ... although he's later seen to have survived the encounter and disguised himself as a reporter.
Bittersweet Ending: After enduring all of the struggles and losses she and her band of fellow Schiff went through, she ends up being the Last of Her Kind. On the bright side, she's finally got to see Okinawa and receives medical treatment from Julia to ward off the Thorn.