Kell is a 21-year-old blood magician, known as an Antari, who possesses the rare ability to travel between parallel Londons. He acts as the official emissary for Red London's royal family but secretly smuggles trinkets between the worlds. He has reddish-brown hair, one crisp blue eye, and one solid black eye that marks him as an Antari. He feels out of place despite his privileged upbringing in the royal palace.

Lila is a 19-year-old thief living on the streets of Grey London with dreams of becoming a pirate. She survives through quick wits and fighting skills. Often disguised as a man to blend in, she possesses an independent spirit and deeply resents owing debts or feeling vulnerable.

Rhy is the 19-year-old crown prince of Red London. He is handsome and known for his social lifestyle and love of celebrations. Beneath his playful exterior, he struggles with his limited magical abilities and worries deeply about his adoptive brother's illegal smuggling habits.

Holland is the Antari of White London, marked by his colorless skin and charcoal hair. He serves the cruel rulers of his desolate world and possesses immense magical strength. He views his own harsh existence as fundamentally different from the comfortable life enjoyed by his Red London counterpart.

Astrid is one of the despotic twin rulers of White London. She has porcelain skin and colorless hair, with dark veins showing at her temples from the use of corrupt magic. She uses intimidation, torture, and strict magical control to maintain power over her magic-starved city.

Athos is the tyrannical twin brother of Astrid, co-ruling the bleak world of White London. He is broader and wears his hair shorter than his sister, but shares her porcelain complexion and dark, magic-stained veins. He views magic as a force to be conquered and dominated at all costs.

Barron is the steady and unflappable owner of the Stone's Throw tavern in Grey London. He operates as an anchor for the local outcasts and maintains a strict but protective watch over the establishment. He acts as a patient father figure to the local thieves.

King Maxim is the ruler of Red London. He presides over a prosperous, magic-rich empire and upholds the strict laws that keep the parallel worlds separated. He expects duty and obedience from those within his household.

Queen Emira is the sovereign of Red London alongside her husband. She projects a regal, caring exterior toward her household, though her primary focus remains the stability and prosperity of her magical kingdom.

King George III is the elderly, ailing monarch of Grey London. Described as having fraying nerves and fragile health, he is one of the few individuals in his magic-less world aware of the parallel Londons.

The Prince Regent of Grey London acts as the practical ruler in place of his ill father. He is domineering and spiteful, openly hungering for the power that the magical worlds represent.

Fletcher is a pawn shop owner in Red London who caters to criminals moving rare items. He bears magical brand marks as punishment for previously breaking the city's highest laws regarding mind control.

Powell is the owner of the Sea King, a run-down vessel in Grey London. He allows Lila to stay on board in exchange for a cut of her thievery, though he opportunistically attempts to exploit her.

Master Tieren is the head priest of Red London's Sanctuary and an expert in magical theory. He previously served as a tutor to the royal household and maintains a calm, authoritative presence during magical emergencies.

Ned is a magic enthusiast living in the magic-less Grey London. He frequents the Stone's Throw tavern hoping to purchase artifacts that might grant him supernatural abilities.