|Family:|| Patrick Penhallow (father)|
Jia Penhallow (mother)
Sebastian Verlac † (cousin)
Aline has been good friends with Alec and Isabelle Lightwood since she was young, particularly because the Lightwoods were family friends of the Penhallows. She lived with her parents in the Beijing Institute for a few years before moving to Alicante.
When she was thirteen, Aline and Jace explored the Brocelind Forest in Idris on horseback and soon got lost. While Aline had been terrified, Jace was fearless and, though it took hours, managed to get them out of the forest.
Aline is at her house in Idris, waiting for her longtime friends, the Lightwoods, to arrive. At the same time, her cousin, Sebastian Verlac, was visiting from Paris as well. When the Lightwoods arrive, carrying an unconscious vampire with them, Aline is curious. She converses easily with the Lightwoods and questions Simon, rather impolitely, about his species.
Aline has a short term crush on Jace. During that time, she kisses him, wanting to know if she is still attracted to boys, only to be interrupted by Clary, immediately putting her in Clary's bad books. However, when the teenagers of her residence were discussing Jace and Clary, Aline comes to Clary's defense. She points out that Jace should lighten up on his over-protectiveness, though she misunderstands why Jace is protective, as she believes they are siblings.
Everything changes one night. Suddenly, the Demon Towers of Alicante seem to go out, and demons swarm into the city. Several break into Aline's house, driving her out into the streets. While outside, Aline is knocked to the floor by a demon who then attempts to rape her. However, Aline is saved by Isabelle Lightwood. Then, she kills the demon from behind before running off.
When Aline is next seen, her mother is being yelled at by Maryse Lightwood. Her cousin, Sebastian, had just killed the youngest of the Lightwoods, Max Lightwood. Aline was in contact with Elodie Verlac, Sebastian's aunt, who sent some of Sebastian's things as well as some pictures. This reveals that the person that was staying with them was an imposter. Instead of telling her parents or the Clave, Aline goes to tell Clary Fray. She hoped that Clary would tell the Lightwoods and that they might forgive her family.
Aline is with Isabelle and Clary as they discuss what they'll be wearing to the party. After she leaves, Isabelle asks whether or not Aline was jealous. To this, Clary replies no, signifying that they were on good terms. She is last seen at the party in Alicante. At some point, Aline came out to her parents, Jia and Patrick. Aline met Helen Blackthorn and they began dating publicly, much to the Clave's disapproval.
When Aline came out to her parents, Jia was worried that Helen would break her daughter's heart and also because Helen is part faerie, a race known for their untrustworthiness. Whereas, Patrick was not happy that Aline had chosen a girl at all rather than a boy, that he mourned selfishly for what he saw as the end of his branch of the Penhallows. The Blackthorns like Aline a lot as she is a calming presence and keeps Helen from fretting.
Aline is seen at the Council meeting to discuss what should be done about Jonathan Morgenstern. She is afterward seen with her girlfriend, Helen Blackthorn, talking to the Lightwoods and Clary. She reveals that the reason she had the guts to ask Helen out was because Alec came out with Magnus inspiring her.
She participates in the battle against Jonathan Morgenstern alongside her girlfriend Helen, the Lightwoods, Simon Lewis, the New York pack, and Magnus Bane. She covers for the group not telling the Clave about the attack by lying to her mother. She said that there wasn't time and that they needed to go when they received the information. She does this as an act of revenge against Jonathan, who killed her cousin Sebastian, as well as a thank you to Isabelle, because she stopped a demon from attacking her.
Aline is at her house with her parents and girlfriend when Helen's siblings and Emma Carstairs arrive at the Penhallow house by Portal after the Los Angeles Institute was attacked. Aline and her parents allowed the Blackthorns and Emma to stay at their home. Aline talked to Clary about her worry over Helen and her siblings and also Emma. Aline, along with Helen, participated in the fight against the Endarkened at the Adamant Citadel. Aline and Helen helped an injured Shadowhunter after the battle.
Aline and Helen along with Alec, Isabelle and Clary witnessed a drunken Simon professing his love for Isabelle which was interrupted by a furious Robert Lightwood. Aline and Helen attended the Council meeting which was interrupted by Matthias Gonzales, who threatened Jia's life and wanted Clary and Jace to surrender themselves up to Sebastian Morgenstern. Alec saved Jia's life by hitting Matthias with his bow and arrow. Aline and Helen along with her mother, Jia, Robert and Maryse Lightwood, Brother Enoch and Brother Zachariah attended the funeral of the Shadowhunters who died during the Citadel battle.
Aline fought against the Dark Shadowhunters and the faeries at the Accords Hall along with her parents, her girlfriend, and the other Shadowhunters in Idris. At the Council meeting after the Dark War, Helen got exiled to Wrangel Island to study the wards and Aline promised to go with her the following week. Aline was among those who attended Jocelyn and Luke's wedding at Three Arrows Farm.
Aline is in many ways Isabelle's opposite. Where Isabelle is outspoken and confident, Aline is conservative and somewhat shy but at times curious. She is very caring toward her friends, the Lightwoods, and tries to console them when Jace was kidnapped. She is hesitant about the topic of Downworlders, being raised in Idris, and asks quite a few questions about them to Simon when they meet. She initially believes that Downworlders don't have souls, and bluntly says so to Simon. The two are a great deal alike. They both say whatever comes into their head's when it comes into their heads.
Despite her hesitant nature, Aline does care deeply for her family as well as the Lightwoods. She doesn't tell the Clave about the actual events occurring during the fight against Jonathan as a form of revenge against him for killing her cousin. This is also payment toward Isabelle, who saved her.
Aline is half-Asian, contributing to her curved cheekbones, round almond-shaped eyes, and small stature, and is said to look a great deal like her mother. She has dark brown eyes, a delicately, pointed chin, and straight dark, black hair. People perceive her beauty differently—Isabelle and Clary both thought she was pretty, and Simon, who thought she wasn't exactly pretty, described her as striking.
Helen Blackthorn is Aline's girlfriend. Aline met Helen sometime after the Mortal War in Los Angeles and they began dating each other despite the Clave's disapproval. Aline and Helen have exchanged family rings which was a serious gesture among Shadowhunters as it is like being engaged. When Helen got exiled to Wrangel Island, Aline promised to follow her there after the following week.
Jia Penhallow is Aline's mother whom she greatly resembles. Aline seems to have a good relationship with her mother. When Aline came out to her and started dating Helen, Jia was worried about Aline getting her heart broken. Jia felt bad for having to send Helen away to Wrangel Island devastating her daughter.
Patrick Penhallow is Aline's father and she seems to have a good relationship with her father. Patrick was disappointed when Aline came out to him and started dating Helen for selfish reasons namely for not continuing the Penhallow line. Not much is known about her relationship with her father.
Alec Lightwood is a family friend of Aline and they are good friends with each other. Aline told Alec that she was inspired by him to came out to her parents and began dating Helen when he kissed Magnus at the Accords Hall before the Mortal War. Alec voted against sending Aline's girlfriend, Helen away to Wrangel Island during the Council meeting after the Dark War.
Isabelle Lightwood is a family friend of Aline. Isabelle gets along with Aline despite their different personalities although they have a tendency to say whatever comes out of their mouths. When Aline was attacked and almost raped by a demon when the Demon Towers went down during the Mortal War; Isabelle saved her life. Aline later repayed Isabelle by helping her friends with the battle against Sebastian at the Burren by lying to her mother.
Jace Herondale is a family friend of Aline. When Aline was thirteen; she and Jace rode over to Brocelind Forest where they got lost and Aline was terrified that they were going to die but Jace was able to get them safely back to Alicante. Aline had a short-lived crush on Jace in which she kissed him only to come to realize that no guy was her type and she eventually realized that she is a lesbian.
Clary Fray is one of Aline's friends. Aline met Clary when she first came to Alicante along with Simon. When Aline kissed Jace which was witnessed by Clary; she was put into Clary's bad books. Eventually, Aline made amends with Clary when she admitted that she was tour one to kiss Jace not the other was around. During the Dark War, Aline confessed to Clary about her worry over Helen and her family and also about Emma.
- City of Glass (first appearance)
- City of Lost Souls
- City of Heavenly Fire
- Pale Kings and Princes (mentioned only)
- Bitter of Tongue (set to appear)
- The Dark Artifices (set to appear)