Wilmur, the secondary protagonist and point-of-view character of the novel, is 15 years old, tall, thin, and gangly, with pale skin, reddish hair, and a “distinguished nose” (13). Like Viola, he was left on Caveat in the care of Hestur. He is the son of Herman and Lenora Ravenspurn de Merlen Stables, and his real name is William. At the beginning of the novel, Stevenson portrays Wilmur in contrast to Viola—he’s more active and daring and usually instigates their adventures. Unlike Viola, Wilmur is outgoing and makes friends easily. He bonds quickly with the crew of the Calamary Rose. As he befriends this crew, he begins to pull away from Viola. He also bonds quickly with the Queensmen aboard the Excelsis, despite their differences from the pirates.

 Wilmur and Viola begin their adventure together, but Wilmur’s character remains constant throughout the novel while Viola experiences significant growth and change. Wilmur grows in height and strength and develops skills as a sailor, but his inherent views of the world do not change as radically as Viola’s, emphasizing him as the one steady, grounding presence in Viola’s life. Their bond epitomizes the novel’s thematic engagement with the importance of chosen family and community. The only true sense of belonging either of them feels throughout the novel is with each other. As Viola tells Wilmur, “I’m on your side, Wilmur, no matter what. I’m your family, and you’re mine, so flog all the rest of them” (420). As the truth of Wilmur’s parentage is progressively revealed, he continues to grapple with the nature of family. He’s angry and hurt to discover his parents are Herman and Lenora/Chase, who never told him of their connection to him, even when they suspected it.

Cadence Chase, the Captain of the Calamary Rose, has long dark hair and brown eyes, with features that are “all proud angles, sharp as steel” (41). Chase has many aliases, including the pirate Scarlet Morning, the gentlewoman Lenora de Merle-en-Sables (or Merlen Stables), Rosselin Morgenstern, Danny-Boy, and Fritz, positioning her as an enigmatic figure at the center of the story’s interlocking mysteries. In contrast with Chase’s appearance, Scarlet Morning is described as having bright red hair in keeping with her name, and she wears a pale mask to hide her face. However, Chase confirms her identity with the star-shaped scar on her left hand, which she claims to have acquired as a child.

Chase is gruff and serious, usually not joining in the festivities with her crew. She becomes obsessed with decoding the Book, believing it holds the key to what she wants—a goal Stevenson keeps hidden for the majority of the novel, reinforcing the story’s mystery. The novel reveals very little of Chase’s identity or backstory. A merchant calls her Lenora, hinting at her past identity, but Herman claims his wife Lenora died 15 years ago. Chase’s version of her life differs greatly from the rumors and legends about Scarlet Morning, though they often share a common origin, highlighting the novel’s thematic exploration of the relationship between story and truth. The truth is further complicated in Viola’s visions, in which she discovers that Chase was working with or for Vesper Argent, who calls her Fritz. The name Scarlet Morning derives from the old sailor’s warning: “Evening red and morning gray, sets the traveler on his way. Evening gray and morning red, brings down rain upon his head” (213), in which she is the red morning that brings storms.

Herman Ravenspurn is the last surviving member of Parliament and the head of the Queensmen. His full name is Herman Adamastor-Pactolus Laurelton Ravenspurn de Merlen Stables. He’s responsible for ordering the purge of the pirate islands, which catalyzed the Pirate Massacre. Herman is a thin, severe, bald man who wears plain black suits and jewelry made from the gilded collarbones and breastbone of a loved one, in the custom of mourning among the “Civilized islands” (238). He is also Wilmur/William’s father. He believes his wife, Lenora, died 15 years ago, and he has been searching for his son ever since. His actions, and the consequences of the Pirate Massacre, haunt him, turning him into a “hollow, passionless man sleepwalking through the ruins of a world he helped to break” (385). Beneath his stern exterior, however, he hopes for redemption. When he finds Hail Meridian alive but ill, he acts swiftly to help her. His promise to Hail Meridian, to serve Viola as his new queen, in the novel’s resolution suggests that Herman will become an increasingly significant character in the sequel.

Hail Meridian was the Queen of Dickerson’s Sea 15 years before the events of the novel. She ruled from her palace on Faire Distance, the most beautiful and elegant of all the islands in Dickerson’s Sea. Hail Meridian is a beautiful girl with long gold hair and striking violet eyes. She claims to be the previous queen, Dearest Ferdinandea’s, distant cousin. However, Stevenson eventually reveals her true identity as a pirate girl named Elize who works for Vesper Argent. She was placed on the throne in a complex scheme to destroy the Civilized islands and bring about a new golden age of piracy.

Hail Meridian suffers from paranoia, visions, and hearing voices as a result of Ves poisoning her with gull blood and marking her with the Silver Circle. She uses the mask of Scarlet Morning to stage her own abduction and murder, causing the Queensmen to declare war on the pirates and leading to the deaths of hundreds or thousands of pirates and innocent bystanders. Hail Meridian sits at the center of the novel’s thematic engagement with The Burdens of Inherited Failure. Though she is one of those responsible for the devastating events of the Great Blow and the Pirate Massacre, she chooses to hide rather than help fix her mistakes. She transfers that burden onto Viola when she declares Viola as the heir to her throne.

Vesper Argent, called Ves, is an important character to the plot despite the fact that he only appears in flashbacks. Though the novel’s conflict arises primarily from external conflicts with the deadly and supernatural elements of nature, Ves is an antagonist working behind the scenes, whose past actions have a direct bearing on the novel’s present. Stevenson uses the device of Viola’s visions to reveal that Ves controls the gulls and the Silver Circle, both forces of chaos and destruction in the novel.

Ves is a tall man, “slight and willowy like a rapier, with impish green eyes and silver hair” (246). He placed Elize on the throne as Hail Meridian as part of his scheme to take over not only the Civilized islands, but of all the pirate courts as well. He includes Chase in these plans, sending her to infiltrate Faire Distance by seducing a nobleman (Herman Ravenspurn). Through context clues, Stevenson indicates that Ves is responsible for the gulls that killed the Requiem Sharks on Wilder’s Green years before, and that he sends the gulls to attack Viola, killing many of Elvey’s friends. As with the name Scarlet Morning, Ves’s name derives from the sailor’s warning poem. “Vesper” means evening, and “argent” is another word for silver or gray.