Tress is a young woman who lives a quiet life on a barren island called the Rock. She spends her days washing windows, caring for her family, and curating a collection of cups brought by visiting sailors. Though she considers herself ordinary and content, her deep care for others pushes her out of her comfort zone when tragedy strikes.

Charlie is the son of the local duke, though he lacks the typical arrogance or ambition of a noble. He prefers weaving stories and spending quiet time with Tress over learning martial skills or preparing to rule. When his father attempts to force him into a political marriage, Charlie actively sabotages the arrangements to stay true to his feelings.

Captain Crow commands the pirate ship operating on the spore seas. She maintains control through fear and violence, harboring ulterior motives for transitioning her merchant crew into piracy. She suffers from a terminal condition that drives her desperate actions across the dangerous oceans.

The Sorceress is a powerful, malevolent entity who rules from a stronghold in the dangerous Midnight Sea. She raids the borders of the Verdant Sea and demands royal souls rather than gold as payment. She is the terrifying figure holding the duke's son captive.

Laggart serves as the cannonmaster aboard the pirate ship. He is fiercely loyal to Captain Crow and actively works to sabotage the ship's weaponry so that they destroy targets rather than merely disabling them. His actions force the rest of the crew into becoming wanted murderers.

Salay is the highly skilled helmswoman of the Crow's Song. Her position grants her unique authority, as ship tradition dictates that even the captain cannot override her steering decisions. She protects the crew, despises the captain's violent escalation, and sails to pay off debts for someone she cares about.

Ann is the carpenter and assistant cannonmaster on the pirate ship. She believes herself to be a terrible shot, a reputation she accepts without much resistance. She is kind and deeply regrets the violence the pirate ship inflicts on others.

Fort is the deaf quartermaster and makeshift cook aboard the Crow's Song. He communicates using a specialized magical tablet he acquired through a trade. He views all interactions through the lens of bargaining, treating conversation as an exchange of equal value.

Dr. Ulaam is the pale, red-eyed surgeon of the Crow's Song. He is a creature from another world who possesses no heartbeat and cold skin, though he finds the term zombie inaccurate. He collects body parts, understands the biology of spores, and offers cryptic medical advice.

Hoid is the narrator of the story and a cursed cabin boy aboard the Crow's Song. In his cursed state, he behaves erratically, speaking in riddles or total nonsense, which masks his true awareness. He is an outsider to this world but possesses knowledge about its dangers.

The Duke rules over the island known as the Rock, managing the kingdom's vital salt mines. He is a calculating and status-obsessed nobleman who values political alliances over personal happiness. He views his son as a tool for securing power and forcefully intervenes when he notices the connection between Charlie and a local window washer.

Lem is Tress's father and a resident of the Rock. He is highly respected among the local men because of his long history of helping others without asking for anything in return. He listens carefully to his daughter and trusts her judgment when she decides to leave the island.

Ulba is Tress's mother, managing a difficult life on the inhospitable salt-mining island. She is practical and protective, initially viewing Tress's plans to leave the island as foolish. Despite her reservations, she helps her daughter prepare for the journey.

Xisisrefliel is an ancient dragon rumored to live beneath the Crimson Sea. According to legends and Captain Crow's research, he possesses the ability to cure terminal illnesses, including spore gestation. He demands a high price for his boons, specifically requiring human servants who do not fear spores.

Flik is a servant in the duke's household. He is anxious and fearful of his employer but possesses enough conscience to secretly provide Tress with the truth about Charlie's disappearance and his final broken cup.

Dirk is the tall, muscular nephew of the duke. When the duke returns from his voyage, Dirk is presented as the new heir and the one who has successfully married a princess, effectively replacing Charlie in the family line.

The Dougs is the narrator's collective term for the various background crew members aboard the Crow's Song whose individual names are deemed unnecessary to the story. They are ordinary sailors trapped in a life of piracy, performing manual labor and relying on the ship's officers for direction.