Gibbet
- The eldest sister strings them up
The eldest of Hank Fieron's daughters, allegedly the personification of a gibbet. She is the only one who can exit the tower without losing her physical form, and so goes out in search of victims to lure to the tower. Despite believing herself to be a wraith alongside her sisters, she has strange memories of a past she's forgotten and it's quickly made clear not all is as it seems with her.
- Dreaming of Times Gone By: She has mysterious dreams about what may have been her past, implying she might not be simply a wraith. Beritoad tells her to ignore them.
- Human All Along: Raymond suspects that she may not be a wraith after all, since she bleeds and wraiths don't bleed. Sure enough she is revealed to be human, although it's complicated.
- Obfuscating Stupidity: She pretends to be an innocent and sheltered young lady who would be a perfect victim for burglars and thieves seeking the treasure of the tower, in order to lure them to their deaths.
Rack
- The middle sister stretches them
The second-eldest of Hank Fieron's daughter, the personification of a torture rack. She loses her human form if too far from the tower and so has to remain inside. Her job is to torture prisoners for Beritoad.
- And I Must Scream: This is her fate if she or Maiden are to leave the tower, as they revert back to their inanimate torture implement forms. The second book reveals that they're both aware during this time.
- Little Bit Beastly: Has a wolf tail and inhuman eyes with slitted pupils.
- Our Werewolves Are Different: Rack looks like a little girl, but she has wolfish features like a tail and her buns looking like ears. During the climax of the first novel, she transforms into a gigantic wolf when she gets angry enough and it's shown that the buns really are ears. She behaves savagely and doesn't recall anything she does during this time.
- Torture Technician: All of the girls torture prisoners to an extent, but it's Rack's job specifically and she's very good at it.
- Unusual Euphemism: Refers to her torture as playing with people, and when she scars up a victim's back with her whip she calls it making a "painting".
Maiden
- And then the youngest sister locks them inside
The youngest of Hank Fieron's daughters, the personification of the iron maiden. She loses her human form if too far from the tower and so has to remain inside. Aside from maintenance of the tower, her job is to kill the tower's prisoners once they've been tortured into madness.
- And I Must Scream: This is her fate if she or Rack are to leave the tower, as they revert back to their inanimate torture implement forms. The second book reveals that they're both aware during this time.
- The Quiet One: She rarely speaks out of the three sisters, being the most reserved and withdrawn.
Beritoad
The "evil god" that the sisters of the tower serve, who currently takes the form of a small frog. He claims to the girls that he can bring their father back to life if they sacrifice enough victims to him. In truth, he's a powerful and evil wraith who's using the girls to help him regain his true form by torturing and killing humans.
- Big Bad: He's the one orchestrating all the evil that happens in the series, and directly launched an attack on humanity before he was defeated.
- Punny Name: His name is a pun on the name of a mythological demon Berith.
Rabiah
Beritoad's wraith familiar that takes the form of a crow, who had left the tower prior to the first book due to a quarrel with Beritoad. He returns in the second book, just in time to help the sisters rescue Beritoad after he's kidnapped by the Crossrosier society.
- Ambiguously Brown: He's one of the only dark-skinned characters in the series, and is known as the "black wraith" presumably because of this. Although his ethnicity, if wraiths even have ethnicities, is not clarified.
- The Dragon: Is this to Beritoad, though he only takes up this role in the second book as he was absent during the first.
- Punny Name: His name is a pun on the name of a mythological demon Decarabia.
Raymond Atwood
A street clown by day and a wraith hunter by night, Raymond hunts wraiths and defends humanity for his adoptive father Romalius and seeks to stop the evil machinations of Torcia Tower. Unbeknownst to most people, he's part wraith himself, being the ill-begotten son of Beritoad himself.
- Antagonistic Offspring: He despises his father for what he did to his mother and for all the evil he does.
- Boomerang Bigot: He despises wraiths, but is himself half-wraith. This is justified since the sketchy circumstances of his conception and who his father is only adds to his hatred of wraiths.
- Childhood Friends: With Liam, the two of them meeting and growing up together in a traveling circus.
- Child Soldier: Romalius has him killing his enemies from a young age, with Raymond killing Hank Fieron when he was ten years old.
- Roaring Rampage of Revenge: Accidental example; when his hometown burned his mother to death for her association with Beritoad, Raymond's rage caused him to unwittingly strike the church with a lightning bolt, burning down the entire town.
Romalius
Beritoad's archenemy and Raymond's adoptive father, as well as the lover of Raymond's late mother Selma. He's a wraith who, unlike most, actively works with humanity to stop Beritoad and sends Raymond on assignments to this end. However, his motivations are in reality more selfish than altruistic.
- Manipulative Bastard: Raymond himself sees him as manipulative of other people and he orchestrates events to give him the advantage over Beritoad regardless of the danger it could put his allies in.
- Parental Substitute: He's this for Raymond, adopting him and hiding the boy's existence from his father.
- Punny Name: His name is a pun on the name of a mythological demon Andromalius.
Lloyd Lowell
A thief from outside the city who heard about the Pot of Baizhu through Gibbet, and hopes to sell it to sin enough money for his ambitions.
- Big Brother Mentor: To his younger brother Zepeto, considering how he takes him along on a theft. Also to Raymond, because of how he reminds him of Zepeto.
- Bitch in Sheep's Clothing: When Lloyd first meets everyone at Stella's Bar, he is charming and polite. Later on, he tells Raymond that it’s an act and he doesn’t care for guys or poor folk.
- Facial Horror: When Benji is examining Lloyd's wounds from his torture, it is revealed that while the rest of his body will heal, his face is too far scarred, and that the sisters were purposefully aiming for it.
- Lovable Rogue: In his eyes at least, considering how he considers himself charming towards ladies.
- Master Actor: Lloyd is perfectly able to show several sides of his personality in public and private, telling Raymond that it’s all just an act. It is also later revealed that Lloyd's main ambition is to become an actor, so he clearly has the experience considering how he played Romalius on stage once.
