Jenna is the Castle’s Princess and Sarah and Silas Heap’s only daughter. The 10-year-old’s “straight black hair and deep violet eyes” (44) set her apart visually from her blond-haired, green-eyed adoptive family. One of Jenna’s key traits is her courage. She wants to resist DomDaniel rather than run from the Castle, and she sneaks aboard his ship instead of waiting for the adult characters to help Marcia: “Marcia rescued me when I was in danger” (442). Another of Jenna’s strengths is the caring temperament she demonstrates by tending to Stanley when he’s ill and by showing the taciturn Boy 412 gentleness and understanding. For example, she responds with sympathy after he reveals her location to the Hunter, an action that endangers her life: “He was as scared as we were. And just think, he’s probably been in the Young Army all his life and never had a mum or dad. Not like us” (205). Additionally, the Princess has a commanding presence that compels adults to listen to her, such as when she makes Aunt Zelda stop panicking and prepare for an impending crisis: “‘Aunt Zelda,’ said Jenna sternly, ‘forget the rabbits. There’s a storm coming’” (466). Jenna’s courage, kindness, and authority help her serve her function as a hero and future leader.

As the protagonist’s sister and the Castle’s rightful heir, Jenna makes important contributions to the novel’s genre and themes. The revelation that she is a lost royal utilizes a popular fantasy trope. In The Struggle Between Good and Evil, the Princess refuses to back down from the Darke Side. Jenna’s development interweaves with the theme of The Power of Family Ties and Loyalty; she goes from worrying that she isn’t a true Heap because she’s adopted to understanding that the ties between her and her family are stronger than blood. She also advances the theme because her loyalty and kindness welcome Boy 412 into his found family.

Additionally, Jenna’s character arc presents The Influence of Power on Identity and Responsibility because she wields her authority as the Princess with mercy, such as when she tries to help the Apprentice and spares the Hunter’s life. Her innate power as a royal awakens the Dragon Boat, allowing the children to rescue Marcia and ensure the happy ending. Jenna grows from a young girl unsure of where she belongs to a future leader who is resolute in protecting her people.

DomDaniel, also known as the Necromancer, is a former ExtraOrdinary Wizard and the novel’s antagonist. His appearance offers visible evidence of his corruption because he has the “telltale gray pallor” (176) and “pitch-black eyes” (516) of a Darke Wizard. The cruel and megalomaniacal villain will stop at nothing to reclaim his lost power and status, as evidenced by his plot to kidnap the infant Septimus to claim the seventh son of a seventh son’s might for his cause. DomDaniel’s selfishness makes the Heap family’s loyalty stand out more. For example, he manipulates and then betrays his Apprentice by draining him of “all life and substance” (522) and leaving him “discarded like an old banana skin.” The remorseless villain shows no guilt for any of his deeds, and he seals his own fate by trying to attack the heroes and steal the Akhu Amulet once again after he escapes from his sunken ship. DomDaniel’s cruelty, manipulative nature, and hunger for power position him as the story’s antagonist and ultimately lead to his own downfall.

As the fantasy novel’s main antagonist, DomDaniel shapes the story’s plot and themes. He sets the rising action into motion when he orders the Queen’s assassination and Septimus Heap’s abduction. The suspense mounts as the Darke Wizard’s power grows, and his defeat at Marcia’s hands during the climax secures the happy ending. His attitude toward power and responsibility contrasts starkly with Alther and Marcia’s: “DomDaniel had been an arrogant and unpleasant ExtraOrdinary Wizard, completely uninterested in the Castle and the people there who needed his help, pursuing only his desire for extreme power and eternal youth” (176). He also plays a key role in the theme of The Struggle Between Good and Evil. The novel’s other villains, including the Supreme Custodian, the Hunter, and the Apprentice, all serve him, establishing him as the greatest threat to the Castle’s peace and the heroes’ lives. Sage presents DomDaniel as irredeemably wicked and relentlessly cruel, forcing kind characters like Jenna and Aunt Zelda to engage in the cosmic battle between good and evil. Both Jenna and Boy 412 discover essential truths about themselves during their struggles against the villain, showing that striving for good can teach people who they really are.

Marcia Overstrand is the Castle’s ExtraOrdinary Wizard, the most powerful magic-wielder in the kingdom. Her majestic purple robes, purple silk cloak, and “specially made” shoes crafted from the skin of a “purple python” (31) reflect the pride she takes in being the ExtraOrdinary Wizard. Her magical might and demeanor make her an imposing figure, although she doesn’t fully realize how much she intimidates others: “Marcia was unaware that most people thought she did scary very well indeed, and was in fact a complete natural at scary” (32). Marcia has a tendency to be haughty and short-tempered with her fellow Wizards. This is sometimes to her detriment, as when she falls for the Supreme Custodian’s trap because she rushes to reprimand Silas: “‘Marcia, is that wise?’ asked Aunt Zelda quietly. ‘I am still the ExtraOrdinary Wizard and I will not be kept away,’ Marcia declared” (333). Despite these flaws, Marcia possesses a deep understanding of Magyk and a shrewd intellect, which she demonstrates by seeing through DomDaniel’s disguise and being the first to realize that the Apprentice is not Septimus Heap. Marcia’s power and cleverness make her an important ally to the protagonist, while the flaws of pride and anger round out her character.

In her roles as the rightful ExtraOrdinary Wizard and the protagonist’s mentor, Marcia figures prominently in the novel’s structure and themes. She sets the story’s events into motion by rescuing the infant Jenna and ensuring that the Heaps raise her as their own: “Tell no one you found her. She was born to you. Understand?” (5). Her capture by DomDaniel’s forces raises the novel’s suspense and ensures Jenna and the young protagonist must take action themselves. Additionally, she shapes the climax and the joyful resolution by defeating DomDaniel and taking Boy 412 on as her Apprentice. Marcia develops the theme of The Influence of Power on Identity and Responsibility by offering a positive example of exercising power responsibly, informing Jenna that she’s the Princess, and helping Boy 412 realize his “astonishing Magykal power” (528). She’s also a key figure in The Struggle Between Good and Evil. The ExtraOrdinary Wizard is the most formidable person on the side of good due to her extensive magical skills, which she demonstrates by besting DomDaniel twice. Lastly, Marcia forges a link between the theme of The Struggle Between Good and Evil and the remainder of the series because her mentorship will prepare Septimus for his role in this cosmic battle.

Aunt Zelda Heap is Silas’s aunt and the great-aunt of Jenna and Boy 412. She has “frizzy gray hair” and “rosy cheeks,” and her “comfortable smile and friendly witch’s brilliant blue eyes” (195) capture her warm and nurturing personality. The “renowned White Witch” (16) has a deep love of plants and animals that befits her position as Keeper of Marram Marshes. Her gentleness and generosity help the fearful Boy 412 learn to trust others, and his fondness for her quirky recipes, which include “eel stew and dumplings” (541), reflects the comfort she gives him. Although Aunt Zelda is openhearted, she keeps a closely guarded secret. She is the latest in a long line of White Witches to tend to the Dragon Boat over the centuries so that the vessel will be ready when the Queen has need of her. Aunt Zelda’s commitment to fulfilling this secret mission confirms her trustworthy nature and significance within the kingdom’s system of power and magic.

As the Keeper of Marram Marshes and the Heap children’s great-aunt, Aunt Zelda plays an important role in the novel’s themes, structure, and the protagonist’s character development. She advances The Struggle Between Good and Evil by countering cruelty with compassion, such as when she spares the Hunter and saves the Apprentice after DomDaniel “drained [him] of all life and substance” (522). Aunt Zelda also offers a significant example of the power of familial ties and loyalty by opening her home to the Heaps when they’re on the run from the Darke Wizard. Much of the novel takes place in the marshland under her protection, and her cottage offers the heroes emotional and psychological safety in addition to literal sanctuary from DomDaniel. Aunt Zelda’s home becomes a vital refuge for Boy 412, giving the protagonist a safe place to discover who he is and what he wants to do with his life. Crucially, Aunt Zelda develops the themes of family and identity when her scrying spell reveals that Boy 412 is Septimus Heap: “‘Sister Moon, Sister Moon,’ said Aunt Zelda, ‘show us, if you will, the seventh son of Sarah and Silas Heap. Show us Septimus Heap.’ Slowly the image of Sarah Heap faded away and was replaced by—Boy 412” (547). Aunt Zelda’s nurturing love helps the protagonist discover his true self, understand what it means to be part of a family, and achieve his happy ending.