Kaz is the 17-year-old leader of the Dregs gang in Ketterdam's Barrel district. Known on the streets as "Dirtyhands," he dresses in elegant tailored clothes, always wears gloves, and relies on a crow-headed cane due to a limp. Driven by greed and a desire to avenge his brother's death, Kaz orchestrates complex criminal endeavors and gathers a specialized crew for an impossible heist at the Ice Court.

Inej is a 16-year-old Suli acrobat who works as the primary spy for the Dregs gang, earning the nickname "the Wraith." Kidnapped by slavers at fourteen and forced into indentured servitude at a brothel, she joined the Dregs after Kaz bought her contract. She possesses remarkable agility, uses knives named after Suli saints to protect herself, and seeks a new purpose beyond Ketterdam's criminal violence.

Nina is a 17-year-old Grisha Heartrender from Ravka, currently working in Ketterdam. She possesses the magical ability to influence the human body, using her powers to make a living while trying to correct a past mistake that left a young man imprisoned. She retains fierce loyalty to her homeland and her fellow Grisha, leading her to initially reject Kaz's heist proposal until he offers a specific condition regarding a prisoner.

Matthias is an 18-year-old former drüskelle, or Grisha hunter, from Fjerda. He resides in Ketterdam's Hellsgate prison following an accusation of slave trafficking. Deeply devoted to his country's nature gods and raised to view Grisha magic as unnatural, he holds intimate knowledge of the Ice Court fortress that makes him vital to the Dregs' heist.

Jesper is a 17-year-old farm boy from Novyi Zem who traveled to Ketterdam for university but fell into gang life instead. He operates as the Dregs' sharpshooter, relying on his customized revolvers and quick reflexes. A restless nature and a severe gambling addiction leave him heavily in debt to his father, providing his main motivation for joining the dangerous mission.

Wylan is the 16-year-old runaway son of a wealthy merchant. He left his comfortable life in the merchant district to live in the dangerous Barrel, adopting a fake name before Kaz recruited him. He functions as the crew's demolitions expert, building flash bombs and explosives, while serving as Kaz's insurance policy regarding the heist's massive payout.

Van Eck is a wealthy Kerch merchant who serves on the Merchant Council. He kidnaps Kaz to offer a dangerous mission: extracting a Shu scientist from an impenetrable Fjerdan fortress. He fears the global consequences if foreign governments obtain a new drug that unnaturally amplifies Grisha powers.

Pekka is the legendary gang boss of the Dime Lions and owner of the Emerald Palace gambling hall. He orchestrates violent spectacles like the Hellshow at Hellsgate prison. His past actions left a lasting scar on Kaz, making him the primary target of the young thief's long-term vengeance.

Brum is the commander of the Fjerdan drüskelle, the elite military force dedicated to hunting Grisha. He trains young men to view magic users as unnatural threats to their country. He maintains strict discipline and commands intense loyalty from his soldiers.

Jordie is Kaz's deceased older brother. Following their father's death, Jordie sold the family farm and brought young Kaz to Ketterdam to seek their fortune, only to fall victim to a devastating con. His tragic death shaped Kaz's entire worldview and criminal persona.

Tante Heleen, also known as Heleen Van Houden, is the proprietor of the Menagerie, a Ketterdam brothel specializing in foreign girls given animal names. She purchased Inej from slavers and subjected her to physical and emotional abuse before Kaz bought out the contract. She dresses elegantly while running her business with ruthless cruelty.

Haskell is the elderly official leader of the Dregs gang. Though he holds the title of boss, he largely relies on Kaz to manage the gang's operations and bring in profit. He originally purchased Inej's contract from the Menagerie on Kaz's recommendation.

Bo Yul-Bayur is a Shu scientist who accidentally invented jurda parem, an incredibly addictive drug that amplifies Grisha powers to dangerous levels. After seeking asylum from the Kerch Merchant Council, he was captured and imprisoned in Fjerda to prevent him from sharing the formula.

Kuwei is the teenage son of Bo Yul-Bayur. He resides in a laboratory within the Ice Court, where his captors keep him isolated and demand his cooperation. His unexpected presence complicates the Dregs' extraction plan as they infiltrate the fortress.

Joost is a young guard employed in the wealthy merchant district of Ketterdam. He wishes for a more thrilling assignment and spends his shifts pining after a Grisha servant, unaware of the dangerous experiments occurring on the estate.

Anya is an indentured Grisha Healer working in Councilman Hoede's household. She uses her Corporalki abilities to perform minor medical tasks until she is forced to ingest jurda parem during a brutal demonstration of the drug's effects.

Hoede is a Ketterdam Councilman and merchant who employs Grisha indentures. He participates in the initial testing of jurda parem on his own servants to demonstrate the drug's terrifying potential to his peers.

Retvenko is a Squaller Grisha indentured to Councilman Hoede. He controls winds to keep merchant ships safe, but he worries about the sudden disappearance of his fellow Grisha within the household.

Yuri is a Fabrikator Grisha indentured to Councilman Hoede. He fell sick and disappeared after Hoede took him away for a mysterious mission, serving as an early victim to the jurda parem experiments.

Geels is the leader of the Black Tips gang in Ketterdam. He attempts to assassinate Kaz during a neutral meeting to claim territory around Fifth Harbor, relying on bribed guards and secret betrayals to gain the upper hand.

Big Bolliger is an imposing member of the Dregs gang who serves as muscle. He secretly betrays his own gang to work with the Black Tips, leading Kaz to deal with him severely during a public confrontation at the Exchange.

Muzzen is an enforcer for the Dregs gang. He accompanies Kaz to Hellsgate prison to help execute a breakout plan, agreeing to take on a dangerous and uncomfortable disguise in exchange for a handsome payout.

Oomen is an enforcer for the Black Tips gang. He participates in a violent assault on the Dregs' ship and severely injures Inej before being captured and interrogated by Kaz.

Specht is an experienced sailor selected by Kaz to captain the Dregs' ship during their journey to Fjerda. He manages the vessel's operations and awaits the crew's return at the designated extraction point.

Nestor is a Grisha Squaller who attended school with Nina in Ravka. He intercepts the Dregs in Fjerda while under the devastating influence of jurda parem, driven entirely by his desperate addiction to the drug.