Clarissa “Clary” Adele Fray (also referred to as Fairchild and Morgenstern) is the sister of Jonathan Morgenstern and daughter of Valentine Morgenstern and Jocelyn Fairchild. To protect Clary, Jocelyn changes her surname to Fray. Clary is described as having long, curly red hair, freckles, and bright green eyes. She is very small and short, “a little over five feet” as first described in City of Bones and often viewed as younger than her actual age. In the first book, Clary is 15 years old, approaching 16, which is the age of Isabelle Lightwood. Clary is an artist, and in the first book, City of Bones, it is believed that she is a mundane, an ordinary human, as she first thought of herself. It is later revealed that she is a Shadowhunter, or Nephilim: a human with angelic qualities. Clary is described as being stubborn and often rushes into dangerous situations without considering the consequences. Her best friend in the series is Simon Lewis. He is in love with her but she is romantically involved with Jace (who uses various surnames). Clary is devastated when she is told that Jace is her brother but later learns that this is untrue. Clary discovers she can read ancient runes that are used by angels, and she can create her own runes, an ability that was caused by the extra angel blood her father, Valentine Morgenstern, administered to her while she was in her mother’s womb. In the first few books, Clary has a tense relationship with the Lightwoods siblings. Alec Lightwood, Jace’s parabatai or best friend, is seemingly jealous of Clary’s relationship with Jace since he thinks she is occupying Jace more than she should, while Izzy Lightwood shows hostility towards Clary at the beginning since she thinks Clary is just a normal human being.

Jonathan Christopher “Jace” Herondale (also referred to as Wayland, Morgenstern, and Lightwood, known as the brother of Clarissa “Clary” Adele Fray in early series) is described as being tall and muscular with scars across his golden skin from faded magical marks called Runes. He has wavy blond hair and golden eyes, and, like Clary, is a Shadowhunter. Jace is among the Nephilim’s best fighters, since Izzy stated that he’s killed more demons than anybody his age, and readily defends his family. Jace is often flirty and insensitive, and is described as projecting a false arrogance due to an insecurity that he is not good enough. Throughout the books, Jace’s biological family remains unknown although he refers to Isabelle, Alec, and Max as his siblings, and Maryse and Robert Lightwood as his parents. In City of Bones, he believes he is a Wayland but at the end of the book Valentine Morgenstern falsely tells him that he is Jace’s father. In City of Glass, Jace learns that his biological father is actually Stephen Herondale. He goes by the surname of his adoptive family, the Lightwoods but changes it back to Herondale upon learning more about his true father. Like Clary, he has special powers which make him swift and graceful, caused by the extra angel blood he received while in his mother’s womb. His parabatai is Alec Lightwood. Parabatai refers to a pair of Nephilim warriors who fight together as lifelong partners; this is represented as a permanent rune that allows both individuals to be connected to each other.