The de facto leader of the Mane Six. As the talented student of Princess Celestia, she aims to uncover the mysteries behind Castlevania, only to become its greatest enemy… and therefore its biggest target.
Arch-Enemy: Makes one in the form of Actrise. However, since it's been revealed that the Castle also has it in specifically for her, it might seem like she has two arch enemies.
Break the Cutie: The Castle is apparently out to get Twilight, and will never stop until it's achieved this goal. Heck, it might never stop.
Bad Dreams: Is constantly plagued by these throughout the first book.
Guile Heroine: The enemies she finds herself up against are way too powerful to take on head-to-head, so Twilight uses her brains to confront them.
Heroic BSOD: Is crushed by one in the final scene of the final chapter of Book One.
The Lad-ette: Her un-feminine qualities are brought up periodically.
A fashion designer on her way up in the industry, Rarity’s world was decimated when her little sister was victimized by the monsters of Castlevania. She now works with her friends toward ridding Equestria of his influence.
Heroic BSOD: Faces probably the most devastating one out of all the Mane Six. It takes her out of the climax of the first book.
My Greatest Failure: Seems to be accepting that she fed Sweetie Belle poisoned food with as much grace as she can. Celestia would only know how she might have reacted if her friends failed to get the cure and save Sweetie Belle in time...
Parents As Ponies: Her biggest grievance with her parents is that they spend so much time as a couple, they seem to forget that their children have specific needs.
Her bright personality is a strong, solid beacon in a world under Castlevania’s influence—which is why Dracula’s minions aim to silence Pinkie’s laughter once and for all...
Twilight Sparkle’s loyal assistant. He lends his aid to anyone who needs it.
Hidden Depths: His deep words of advice to Shatterstorm were really just passages he’d memorized from philosophy books he’d read in his pastime. Even so, he might have tricked Shatterstorm into thinking he’s wise beyond his years.
Hurting Hero: Several of the Mane 6 come away from interactions with Aeon noting that he seems to be so hurt that, really, it's the only reason he can keep going at all — he's seen and felt so much suffering, sorrow and guilt that attempting to stop Dracula is the only thing that keeps him sane.
It's All My Fault: By the end of the first book, he's dropped hints that he was the one who scattered Dracula's parts in hopes of preventing future risings, causing the resultant invasion of Equestria.
Book 1.5 confirms this, revealing that he was manipulated into doing so by Galamoth, who wanted to usurp Dracula's position. The Mane Six comfort him, telling him not to blame himself.
Man in White: In his natural form, he dresses all in white. In his pony form, he appears as a white unicorn stallion.
Secretly Dying: As revealed in Book 1.5 his powers are waning, which indicates this is happening to him.
A young man from the far-flung future, Soma Cruz is the reincarnation of Dracula himself. As such, he is a talented fighter and thinker, able to possess the souls and abilities of Dracula's accursed minions.
The Belmont. Not the successor. Not the latest of the lineup. THE Belmont. Dracula was supposed to have finally perished by his hands in the year 1999, but thanks to the Castle's escape from the timeline, it seems he must perform this act twice.
Chick Magnet / Nerds Are Sexy: Implied, judging by the reaction of Twilight's friends when they see his picture. So much so that they start immediately teasing Twilight about him being her boyfriend/crush.
The Princesses of Equestria. Their regal duty to keep their home and subjects safe from harm is ripped from them the moment the Castle arrives.
It's All My Fault: Celestia blames herself not only for being caught off guard by Dracula's forces, but is also implied to be carrying guilt for the other times she's been in no position to help her subjects.
Trickster Mentor: Celestia once hid Twilight's photo album on her using a spell that would keep its unique "aura" undetected by unicorns.
A young earth pony who, for reasons unknown, receives nightmarish visions from Castlevania itself. What is its design in terrorizing this seemingly ordinary mare...?
Break the Cutie: Roseluck was pretty well-adjusted near the start of the first book, but one near-death experience and a series of Bad Dreams later, she finds herself straight into Broken Bird territory.
The Grotesque: The way he’s described in the text paints an unflattering image for him.
Jerk Ass: This is the real reason he has no friends. As Twilight points out, he might be creepy-looking and his special talent might be unnerving, but he never once tried to be friendly to the living ponies and prove there's more to him than his cutie mark implies.
A travelling beauty who rolled into Ponyville a day or so before it was overrun with zombies. Her air of mystery and alluring appearance have captured the hearts of many stallions, but what hides behind her beautiful face? Is it good… or evil?
I Have Your Wife: Implied to be the reason she's still working with Dracula's minions even after refusing to poison the foals.
Mare In White: Save for her magenta eyes and red stars cutie mark, Marble's color scheme is extremely pale.
Mind Screw: So she isn’t Marble, but actually Actrise, except that she isn’t Actrise, just possessed by Actrise, but she still isn’t Marble because she’s actually White Dwarf because there never was a Marble to begin with.Everypony got all that?
Eviler than Thou: The aura given off by just his rib is described as being worse than Nightmare Moon, King Sombra, and even his own minions.
Outside-Context Villain: The one strength of Dracula's that trumps anything the ponies of Equestria could have done. Nopony expected his forces to suddenly appear and attack.
The Unfought: Despite the fact that his influence is everywhere (Much like a certain otherBig Bad we could name), the Mane Six never cross him in the first book. Hell, he never even makes an appearance!
The loyal retainer of Dracula, Death is not actually the spirit of death itself, but a demon in the familiar shape of the Grim Reaper.
Creepy Souvenir: Collects the voices of people he kills as these. Upon entering Equestria, he decides he'd rather collect pony cutie marks instead...
The Dragon: To Dracula. Of course, the fact that the boss is still incapacitated means that Death is the one calling the shots right now.
She acts as an intermediary so Dirt Nap can make one with Aguni.
Demonic Possession: Possesses Marble/White Dwarf when she refuses to poison the foals in the hospital.
Evil Counterpart: To Twilight Sparkle. Intelligent, crafty, talented with many forms of magic, plans and plots everything down to the last possible detail. If it weren’t for her more-experienced air and complete disregard for sentient life, she’d be Twilight Sparkle herself.
Moral Event Horizon: Poisoned many of Ponyville's foals to blackmail Dracula's rib out of Twilight. Before that, she even casually experimented the poison and cure on sick foals just to make sure they worked. And then after that, she just keeps going.
Villainous Breakdown: When she realizes that Twilight has cast a spell that'll more effectively hide Dracula's body parts, she starts screaming Twilight's name while beating the Chronomage (who was unfortunate enough to be standing nearby) bloody with her staff. This only lasts a few minutes, however, and she pulls herself back together.
Would Harm A Child: Her backstory is that she sold 100 children, including her owndaughter to Dracula for immortality and magical powers. So, naturally, she has no qualms about using a horrific poison on foals to blackmail Twilight into giving her Dracula's Rib.
Alice Allusion: To start with, he's a bipedal white rabbit who wears a waistcoat, carries a watch and is obsessed with time to the point he can manipulate it. The Chronomage goes beyond the pale by also speaking in nonsensical, often-rhyming gibberish of silly portmanteau words and completely made-up words, as well as wielding the Vorpal Sword from "Through the Looking Glass", which itself has a blade comprised of pure gibberish-words.
Dark Chick: While not unafraid of physical violence, he's the weakest and most support-orientated of Dracula's minions; the actual female of the group, Actrice, is the leader and its main magic-based provider of firepower.
What Measure Is a Mook?: Applejack kills them fairly early on, and doesn't even stop to consider the act until near the end of the first book. This is ironic because the Dead Mate was basically a one-of-a-kind Mook in Super Castlevania IV.
Uncanny Valley: Invoked In-Universe: Bon Bon notes that, despite the fact she's of a different species and has only seen one human by this point, the Mud Men's crude imitations of human faces really makes them creepy.