Half Bad

Marcus is Nathan’s biological father but does nothing to rescue his son from the Fairborns. He is the most powerful of the Blood Witches because he has acquired multiple magical abilities by eating the hearts of the enemies he has killed. Marcus only makes one brief appearance in a chapter at the book’s end. He is described as an older version of Nathan and has occupied his son’s thoughts for years.

Marcus is considered evil by the Fairborn Council and is their greatest enemy. He has also aroused the anger of Mercury, who wishes him dead. Although he has committed many crimes and is generally described as evil, he arrives in time to conduct Nathan’s Giving Ceremony and make his son a true witch. He has only kept his distance because of a prophecy that Nathan might kill him. By the novel's end, Marcus remains a morally ambivalent figure whose goodness or badness has yet to be determined in future books of the trilogy.

Gran is an old Fairborn Witch whose Gift is potion-making. She is Nathan’s maternal grandmother and raises him after his mother’s suicide just as she does her other three grandchildren. While she is strict, she tries to shield Nathan from the restrictive mandates of the Council, taking him on trips to Wales and allowing him more freedom to roam than the authorities wish. She is eventually deprived of custody of Nathan and is investigated by the Council for disobeying their orders. Gran eventually dies while Nathan is still encaged. A comment by Arran late in the book suggests that she might have poisoned herself. 

Mercury is a very ancient Blood Witch who grants favors to other witches for a price. She can control the weather and conjure up thunderstorms when she is angered. Mercury bears a long-standing grudge against Nathan’s father and wants to see him dead, which is her motivation for promising to hold Nathan’s Giving Ceremony.

Mercury’s plans go awry when she sends a team to steal the dagger that could kill Marcus. She hopes to persuade Nathan to use it one day, but circumstances take the weapon out of her reach. By the novel's end, Mercury puts Annalise under a sleeping spell, intending to use her as leverage to get Nathan to kill Marcus in the future.

Annalise is a pretty blond Fairborn Witch who attends secondary school with Nathan. The young people grow attached and take every opportunity to meet in secret. Eventually, Annalise is used as bait by her brothers to lure Nathan into a trap. Afterward, her family never trusts her, and the Council investigates her for conspiring with Nathan. At the end of the story, she flees to Mercury to escape persecution and is briefly reunited with Nathan. Mercury places her in a trance, planning to use her as leverage to control Nathan. By the end of the novel, Annalise still hasn’t awakened.

Gabriel is a teenage Blood Witch who initially acts as Nathan’s emissary to Mercury. He is described as handsome. Because his Gift is shapeshifting, he has turned himself into a fain and can’t seem to undo the process, though Mercury promises to help at some point.

Gabriel shares an apartment with Nathan while the latter waits weeks for Mercury to see him. As a result, the two teens become friends, but Gabriel wants an even more intimate relationship with Nathan. Rose tells Nathan that Gabriel would die for him. At a critical juncture, Gabriel creates a diversion to lead a band of Hunters away so Nathan can escape. This unselfish act might cost his life. By the end of the story, Gabriel’s fate is unknown, but Nathan vows to search for his friend.

Rose is Mercury’s attractive assistant and is regarded as a daughter by the elderly witch. Although she is a Fairborn by birth, her temperament identifies her as a Blood Witch. Rose possesses the unusual Gift of transforming into a mist that confuses and disorients people, which allows her to slip about unseen. She is friendly to Nathan and teases him about Gabriel’s crush. At the novel's end, Rose succeeds in stealing the Detheridge dagger from inside the Hunter headquarters but is shot and killed while escaping.

Celia is a tall, athletic, Fairborn Witch who becomes Nathan’s keeper and trainer. The Council puts her in charge of the boy for two years, during which time she locks him in an outdoor cage at night. Celia is more like a drill sergeant than a jailer. She makes sure that Nathan gets plentiful physical exercise and a healthy diet. She also puts him to work tending chickens and chopping wood.

Celia seems to form an attachment to Nathan and is genuinely disturbed when the Council orders the boy taken away before his 17th birthday. Despite her muted affection for Nathan, she indicates that she would execute him if ordered to do so by the Council.

Arran is the youngest of Nathan’s three half-siblings and the one to whom Nathan is most attached. They are only two years apart in age, and Nathan recalls many fond memories of Arran’s gentle kindness while they were growing up. Like their mother, Arran’s Gift is healing, and he eventually goes to Cambridge to study medicine. Through a video, Arran tells Nathan that he always believed the latter was a good person, no matter what the Council says.