|“||— you were a fool to trust her, little sister. She likes to be on the winning side of things, the Seelie Queen.||”|
The Queen, through her personal knight Meliorn, requested an audience with the Shadowhunters of the New York Institute to discuss the impending war with Valentine Morgenstern. Meliorn used his connection to Isabelle Lightwood to pass the message on through her. Upon their arrival, with the mundane Simon Lewis, the Queen told the group that she would decide on whose side she would take.
Seeing that the apparent siblings Jace and Clary were in love, the Queen then tricked Clary into ingesting food from the Court, thus tethering her to the Court until she decided to let them go. The Queen told her that she would release her if she kissed "whom she most desired", knowing it was Jace.
Evidently, she decided to take the Nephilim's side as faeries took part in the Mortal War. Some time after, she showed herself to Clary and asked her for a favor—one she would owe her and return if she needed it in the future. She asked her to suggest to Luke to make Meliorn the Council representative of the fey. Clary refused, not wanting to risk her trickery and insisted that she already had everything she wanted.
Despite Clary's refusal to help, Meliorn was still assigned the Council seat, and the Queen once again offered an exchange of favors with Clary. Through Kaelie, the Queen arranged for Clary to receive a bell that Clary should simply ring once her need for the favor arose. Clary reluctantly accepted the "gift", though was determined to never ring it.
After Jace went missing, Clary became desperate enough—just as the Queen had predicted—to come to her and ring the bell. She offered to help Clary and her friends find him if she retrieved a pair of faerie rings—which she claimed to have belonged to her father—from the New York Institute. Clary agreed to do it but decided to keep them to use in her own crusade to save Jace, just as she had expected.
Clary went on to join Jace and Sebastian Morgenstern as a spy. While Clary and Simon, the keeper of one of the stolen rings, used the rings to communicate, the Queen listened in on their plans through her own connection to the rings. She later sent Meliorn to meet Sebastian in Prague to tell him that they will fight with him. The Queen and Sebastian then began to secretly communicate through Clary's ring.
The Seelie Queen, always on the lookout for an opportunity, decided to form an alliance with Sebastian Morgenstern and even began a sexual relationship with him. She supplied Sebastian with necessary information, forces, and other favors. During the siege of the Adamant Citadel, she provided Sebastian a means to enter the land of the Citadel, to conceal the greater part of his Endarkened force and himself, as well as a means to retreat.
Later, when Jace, Clary, Isabelle, Alec, and Simon secretly Portaled into Faerie to find a way into the demon realm Sebastian is based out of, they finally discovered from a conversation between the Queen and the leader of the Wild Hunt, Gwyn ap Nudd, that she was allied with Sebastian. Meliorn alerted her to the presence of the hiding group, she lost her composure and, in a rare instance, showed genuine surprise and anger, and once more when Alec killed Meliorn.
Nevertheless, the Queen agreed to escort the group to the path that would lead them to Edom, knowing that leading them to Sebastian would be taking them to their deaths. At Jace's demand, she promised neither she nor any in her court would by word or deed reveal that the group came to Faerie. After their departure, she used her enchanted fey mirror to contact Sebastian and informed him that the group has left and are on their way, and as fey cannot survive in Edom, he must exact vengeance for them both.
After Sebastian and his army's demise, the fey were left in a tenuous position and were sued for their involvement with Sebastian. Her handmaiden, Kaelie Whitewillow, arrived at the Council meeting as the new Faerie representative. On behalf of the Seelie Court, she was forced to agree to a humiliating and crippling peace treaty for the faeries, with their only advocate against the unfair terms being the warlock representative Magnus Bane.
In 2012 the Queen, who had been secluded in her Court for years, sought out Julian Blackthorn, who was staying the night in her Court after rescuing Kieran from the Unseelie King. Through her scrying glass she showed Julian what was happening outside the Faerie lands; his uncle Arthur Blackthorn had confronted Malcolm Fade and Julian watched the warlock kill Arthur and successfully resurrect Annabel Blackthorn, only to be killed by her. The Queen explained her reasons for showing that to him, and surprised him by revealing that she knew of his feelings for Emma Carstairs and also knew of a way to break the parabatai bond.
The next day the Queen spoke with the rest of the Shadowhunters and offered them a bargain; in exchange for finding and retrieving the Black Volume of the Dead in order for her to rescue a stolen member of her Court from the Unseelie King, she would pledge her aid to the Clave to help them defeat him. As the Clave would not refuse her help this would result in the Cold Peace being ended, and Helen Blackthorn returned from exile. Eager for the return of their sister the Blackthorns agreed, and the Queen led them to a group of faerie steeds waiting to take them home.
As the Shadowhunters were leaving, the Queen made a remark about Mark and Kieran to Emma, who turned on her and stated that she was untrustworthy. Surprised, the Queen lost her composure and let her true self show, all her anger and viciousness. Insulted by Emma she could only watch her depart, infuriated by her remarks.
As a faerie, the Seelie Queen displays her people's nature of manipulating quite well, wherein since they cannot lie, they weave words together without giving the whole truth, leading others to give into the faeries' demands. Apparently, it gives her pleasure to mess with people who are in love, like Jace and Clary, as she finds the emotion to be ridiculous.
The Queen is said to be a lovely, slender woman with long scarlet hair and clear, blue eyes. As a faerie she also has slightly pointed ears.
By 2012 the Queen has grown thin to the point of gauntness, though she is still beautiful, and wears an intricate golden circlet for a crown
- Sebastian Morgenstern: The Seelie Queen had both an alliance and a sexual relationship with Sebastian Morgestern during the emerging Dark War. She notes that he's her first mortal lover in ages—and the first in a long time to make her smile—with the Queen calling him Sebastian out of respect considering many Fey themselves prefer to not be addressed by their "true name". She regarded their relationship as a lovers' relationship, though one in which they each kept a dagger at on another's backs, ready to stab and betray if needed.
- Meliorn: The Seelie Queen was one of Meliorn's few true allies. Despite the fact that he was half human, the Seelie Queen took a liking to him and made it known that he was welcome at her court, which he never would have had without her. She treated him as a full faerie—better, even—and swiftly punished anyone who treated him badly. The Seelie Queen is known for being cruel, but this was one instance in which she showed something close to kindness, and Meliorn repaid her with his undying loyalty.
- Vampires, Scones, and Edmund Herondale (alluded to)
- City of Ashes (first appearance)
- City of Glass
- City of Fallen Angels
- City of Lost Souls
- City of Heavenly Fire
- Born to Endless Night (mentioned only)
- A History of Notable Shadowhunters & Denizens of the Downworld
- Lady Midnight (mentioned only)
- Lord of Shadows