|“||I watch my brothers give their hearts away and I think, Don't you know better? Hearts are breakable. And I think even when you heal, you're never what you were before.||”|
Isabelle Lightwood is a Shadowhunter currently under the New York Conclave. She is the only daughter of Robert and Maryse Lightwood, the sister of Alec and Max, and the adoptive sister of Jace Herondale.
She was about ten years old when Jace Wayland was adopted into their family. Hearing from her mother that Jace had witnessed the death of his own father, Isabelle, who liked the feeling of being wanted, had expected Jace to come to her like a scared child needing comfort. Instead, she was disappointed when Jace turned out to be independent, brave and seemingly self-possessed, among other traits that slightly reminded Isabelle of herself. Eventually, when Jace made it clear that he saw Isabelle as a possible training partner and equal, she grew to love him as a brother.
Some time before Max's birth, their father had an affair with a woman she didn't know, later finding out from her mother when she was thirteen and keeping it a secret from almost everyone, since then. Because of this, Isabelle became distrustful of men and found herself not believing in love.
Years later, Isabelle was in a tightly knit group of trainee Shadowhunters with her brothers, Alec and Jace. The trio had developed a working dynamic that they often incorporated during their hunt for demons. Over the years, Izzy also developed a somehow promiscuous attitude, dating anyone whom her parents would most likely disapprove of, such as the faerie Meliorn and even a ghost.
Early in 2007, Isabelle, Alec, and Jace were staking out demons at the Pandemonium Club, a club often frequented by demons looking for victims. Isabelle acted as bait, seducing and luring an Eidolon demon—who was initially oblivious to the fact that she was a Shadowhunter as her runes were covered with the long sleeves of her white gown—into following her to a supply room, while her brothers followed to kill the demon.
At this point, several of the demons they have cornered and encountered had been claiming that the cruel leader of the Circle, Valentine Morgenstern, had returned from the dead. Unbeknownst to them, Clary Fray, a Shadowhunter who was raised as a mundane, had followed them into the supply room. Clary later showed herself and stopped Jace from killing the demon, distracting Jace momentarily before he went on to kill the demon. Surprised and annoyed, Isabelle tied her wrists with her whip and chastised her. Isabelle thought she was a clueless yet Sighted mundane and even mistook her for a pixie because of her size. When the cops arrived, Isabelle and her brothers left unnoticed.
When Jace brought a wounded and runed Clary back to the Institute the next evening, Isabelle was tasked with looking after her in the infirmary. She apparently did not believe that Clary would recover and hoped that it wouldn't be necessary to call on the Silent Brothers, who creeped her out, until she woke up three days after. She lent her clothes and told Clary a bit about Jace before telling the others that she was awake as Clary was set to meet their tutor, Hodge Starkweather.
When Jace and Clary brought Simon Lewis into the Institute with them, Isabelle rebuked Jace for bringing another mundane, knowing that Hodge would do the same. They walked in on her making soup with weird ingredients, which she was eager to let everyone taste. Simon, deciding to try and make Clary jealous, acted as if he was completely captivated by Isabelle and volunteered to try her soup. Jace later told Simon that she would break his heart as soon as she got sick of him.
For a mission where they had to attend a party thrown by the High Warlock of Brooklyn Magnus Bane, Isabelle lent Clary her clothes to help her blend in. While Isabelle fixed up Clary's hair, the other girl asked her about Alec being gay. Isabelle did not deny it but asked her to keep the secret to herself, explaining to her Alec's situation and the Clave's non-acceptance of homosexuality.
At the party, while the others spoke to Magnus, Isabelle was with Simon when he had a drink that turned him into a rat. When Simon went missing, Isabelle felt guilty, though she didn't show Clary and only opened up to Alec about it. When Clary and Jace returned to the Institute the next morning with Simon, Isabelle fussed over the two boys in the infirmary.
Isabelle was present when Clary remembered where her mother hid the Mortal Cup and went along with the group to Clary's apartment to retrieve it.
When Alec got hurt from a demon attack Isabelle stayed behind at the Institute while Jace, Luke, and Clary went to meet Valentine.
Worrying about Jace
Some time later, Isabelle sent Clary a text telling her that the Inquisitor was coming to talk to Jace. When Clary arrived at the Institute, Isabelle and Alec explained to her that the Inquisitor threw Jace in jail as he angered her. Clary went with Isabelle and Alec to save Jace after the Silent City was attacked and they found that all of the Silent Brothers had been killed.
Izzy also went to the Faerie Court along with Clary, Jace, and Simon. She was also present when Clary, Jace, and Raphael buried Simon, necessary for him to become a vampire.
While Jace was being trapped by the Inquisitor, Isabelle and even Max protested that Jace wasn't Valentine's pet, while Alec seemingly turned on Jace and sided with the Inquisitor. Isabelle, not knowing her brother's ruse to remain on the Inquisitor's good side, became furious at Alec. Both she and Max refused to talk to Alec until they found out that he had been lying and had in fact helped break Jace out of his cell.
Isabelle later barged into the library where Imogen was to communicate with Valentine through his Projection. Isabelle was furious when she found out that she was putting Jace's life on the line in exchange for the Mortal Instruments already in Valentine's possession and called Imogen out on her choices, especially once Valentine finally revealed to her that Jace wasn't his spy. After the meeting, the immediately available forces of the New York Conclave charged Valentine's ship, with Isabelle joining in the battle.
Upon being called for an urgent meeting in Idris, Isabelle was meant to be leaving for Alicante with the rest of the Lightwoods, Jace, and Clary. However, the Institute was attacked by a group of Forsaken and so they were forced to leave through the Portal early. Taking Simon with them and leaving Clary behind. While in Alicante, Isabelle and the group met Aline Penhallow and Sebastian Verlac.
Later on, Alec, Isabelle, Aline, Sebastian, and Max were attacked by demons that took Aline. Isabelle went to find out what was going on as Alec hid Max. Alec found her and then went out to fight as she, Sebastian and Max hid inside the house. Isabelle went upstairs to get weapons, leaving Max with Sebastian, so that they could protect themselves if they were attacked. When she came back downstairs she discovered Max was gone just before Sebastian hit her over the head with a hammer, she almost died. Max was killed by Sebastian. When Max died, he held on to a little wooden soldier Jace gave him when he was little. Isabelle kept on telling herself that she should have been there for him to hold on to, not a 'stupid little toy'.
After the attack, Clary and Simon went to visit the Lightwoods, who were grieving the death of Max, and discovered that Isabelle has been locked in her room all day and hasn't been talking to anyone. When Alec and Jace tried to comfort her, she refused to let them in. She continually blamed herself for what happened, saying that if she listened to him about him sighting someone (Sebastian) climbing the demon towers in order to get demons in. She just dismissed his idea as his wild imagination. But he was right. The only person who she let in was Simon, surprising both Jace and Alec. Simon went upstairs to visit her and they fell asleep together, not sexually. She said his presence made her feel better. Although she still blamed herself, she had forced herself that she must avenge his death by killing Sebastian. She did end up beating him up, badly.
The next day, Clary discovered Isabelle and Simon making breakfast together. At this time, Clary asked Simon to leave the room in order to talk to Isabelle alone. When Simon left Clary talked to Isabelle about Jace and why he left. Isabelle told Clary that she never knew what it was like to be a real Shadowhunter and that if Jace died it wouldn't be like Max's death.
After Clary talked to her mom and found out that Jace wasn't her brother and that Sebastian (or Jonathan) was the true son of Valentine, Clary found Isabelle and Alec and told them the goods new first, after telling Simon. Isabelle then found Magnus Bane before the battle began so that she could learn the tracking spell in order to find Jace.
Once Isabelle snuck through the Portal, she found Jace fighting a losing battle against Sebastian. Isabelle helped fight off Sebastian while also avenging Max. With Isabelle's help, Jace was able to kill off Sebastian though very weak.
Learning to love
Some time after, Isabelle met Simon at Veselka, where he expressed his disbelief about ever being able to attract a girl like her. Their date was interrupted when one of Camille Belcourt's subjugates arrived for Simon. Isabelle was uncomfortable with the idea of letting him go to meet with Camille, but he reminded her of the Mark of Cain and insisted on going alone.
At one of Simon's gigs with the band, she and Maia Roberts both found out that he had been dating them simultaneously, claiming that neither had really proclaimed their relationships exclusive. Both promptly broke up with him.
When Simon received a note saying that his girlfriend had been captured, he called Isabelle—along with all his ex-girlfriends—to check that she was alright. She was still angry and told him to leave her alone, though he was glad that she was unharmed.
Isabelle saved Clary when she was attacked by a demon while she tried to find out more about the clan that had been giving demon blood to babies.
When Simon disappeared, Isabelle gathered Alec, Maia and Jordan to rescue him from the Greater Demon Lilith at the Church of Talto. When the battle was over, Isabelle explained what happened to the Clave, and she and Simon made up. They later discovered, however, that Jace disappeared with Sebastian's corpse.
Isabelle grew anxious about Jace's whereabouts. After two weeks, the Clave decided to de-prioritize the search for Jace and Sebastian, devastating Isabelle. She, Clary, Alec, and Simon then decided to commence a searching of their own.
To find out more about Sebastian's plans, Clary joined him and Jace without informing the others. They received updates from her through the faerie rings and the telepathic connection it gave her and Simon. When she told them that they Jace was bound to Sebastian, they looked for ways to sever the bond. Desperate, they summoned Azazel, a Greater Demon, hoping he would have a solution. He asked them for one happy memory each in exchange, which they reluctantly gave up. He then proclaimed that his solution would be his release, after which he would take Sebastian back to Hell. Because this entailed the demon's freedom, the team refused, and the demon was dismissed.
However, Azazel did mention that a strike from Heaven, or an angelic weapon, could in theory harm Sebastian without hurting Jace, essentially breaking the bond. With this idea in mind, they decided that a visit to the Iron Sisters may prove fruitful. Being the only woman in the group, and thus the only one who could travel to the Adamant Citadel, she decided to go, with Jocelyn offering her help. When they met, the Sisters told Isabelle that she would make a great Iron Sister, an idea she quickly rejected. They then informed them that the only way to separate Sebastian from Jace without killing Jace was to use a heavenly sword.
Isabelle's relationship with Simon improved over time, with Simon spending some nights with Isabelle telling her stories, even Star Wars. When Simon decided to be the one who summoned Raziel since he had the Mark of Cain and thus more chances of surviving, Isabelle was very worried. Fortunately, Simon succeeded and acquired the sword Glorious, but the Mark of Cain was removed by Raziel. Isabelle relieved told him that he was no longer cursed.
Following their arrival at the Burren, Isabelle fought alongside the rest of the Nephilim against Sebastian and his dark army. She survived the battle without any serious injury and returned to the Institute where she and Alec took care of Jace, who was unconscious due to the fact that he was stabbed by Clary with Glorious in order to separate him and Sebastian. After Jace regained consciousness, the siblings shared a very touching moment together.
The Dark War
Isabelle and the others provided the moral support for Jace, who trained with Jordan Kyle to control the heavenly fire by meditating. After the attacks on Institutes by the Endarkened army, Maryse Lightwood told everyone to pack their things and leave for Alicante. When they were about to go through a Portal, Simon and Isabelle talked about her trip to Idris. When Simon admitted he wished he was going with her, she assured him that he was safer in New York and away from Sebastian. The conversation changed to Isabelle and the possibility that Simon could get hurt in a relationship with her, which Simon said was worth the risk, touching her deeply. She gave him her ruby necklace to wear while she was gone, in order to protect himself until she returned. He started to tell her he loved her, but she cut him off, not wanting him to say it under these circumstances.
Once in Idris, Isabelle was visibly upset by their parents lack of interest in each other. Alec made the mistake of replying, "A lot of people split up when they have a child who dies," which enraged Isabelle so much that she stormed off out the house.
Back at the Gard, Isabelle attempted to follow the others to the battle for Adamant Citadel, but was stopped by her father. Furious with him, she shouted that Max's death was his fault, and told him, and Alec and Maryse, that she knew about how he had an affair before Max was born, and accused him of being happy about Max's death, as it freed him of responsibilities. She then fled, only to find, just arrived from New York, Simon. Still hurting from her argument up at the Gard, Isabelle was relieved to see him and embraced him. To explain how he had come to be here, Simon and Isabelle retreated to her house.
Isabelle rummaged through Alec's clothes to try and find something for Simon to wear. She filled him in on what had been going on in Alicante since they came here, and what was happening now, but did not mention any personal feelings. Isabelle, trying to forget about her arguments with her family, deflected his questions and attempted to seduce him. The two of them, jokingly role-playing as costume-drama-like characters, ended up together in Alec's bed, before Alec himself arrived in the room. He was horrified to find the two of them together, and from him, Simon found out about Jace and Clary having gone through the Portal. He and Isabelle argue and she took back her pendant. After that, they went to the Basilias.
After they found out that Downworld leaders, along with Jocelyn, were captured, Sebastian demanded Clary and Jace in return for peace. While they were given two days, Clary, Jace, Simon, Alec, and Isabelle escaped through the faerie tunnels to the other dimension, Edom.
When Isabelle was mortally wounded in the fighting, they returned to the caves and Simon was able to save her by using his own blood, which as a Daylighter had restorative powers. When Isabelle had woken up, the two of them found themselves alone together, and they both shared what they saw after crossing over to the demon realm. Isabelle was initially disgusted to hear of Simon's vision, though aware that each vision was in some way wrong, and quickly forgave him. The two finally "DTR"ed and admitted their love for each other. Alec again walked in on them kissing, and despite his earlier comments was once again horrified by what he was seeing.
After a trick pulled by Clary, Sebastian was defeated. Nonetheless, they were left imprisoned in Edom as Sebastian had sealed all the exits. Magnus called on his father, Prince of Hell Asmodeus, who then demanded Magnus's immortality in return for a way out of his realm. Realizing that Magnus, given his centuries of life, would die if this happens, the group refused to let him sacrifice himself. Simon then volunteered his immortality, which would not kill him given his short mortal life, as well as his memories of the Shadow World and his friends in Magnus's stead. Simon refused to be swayed and insisted on doing it for their safe return home.
Some months after, during which the group tried to maintain a level of normalcy in their lives after the war, Isabelle and Magnus accompanied Clary and watched from afar as she approached the now mundane Simon. When Isabelle saw the flyer for Simon's band and saw that he had named them "the Mortal Instruments", she and Magnus realized that Simon may regain his memories if urged. The pair then approached him and told him of his forgotten past. Magnus offered to try and restore some of it with magic but then concluded that the rest might return to him if he tried to become a Shadowhunter.
During Jocelyn and Luke's wedding, Simon told Isabelle that he hoped to be with her as the man she deserved, as the hero they knew he was. In the weeks leading up to Simon leaving for the Shadowhunter Academy, where it was agreed that Simon would attend to train for his potential Ascension, Isabelle remained distant and standoffish. Shortly after he left, Isabelle went to the Institute, claiming to be a volunteer guest lecturer—the first one for the reopening year, in fact—but really only meant to publicly 'DTR' with Simon and threatened anyone who would dare make a move on and against him. After making her speech, the abashed Isabelle quickly left the room. Simon followed her and told her that he couldn't be her boyfriend anymore as he did not want to disappoint her by not remembering and living up to his past self. Isabelle was hurt by this and tried to simply shrug it off, telling Simon that she will no longer wait for him.
When the Academy sent the students after a rogue vampire in New York, Isabelle was among the group of Shadowhunters keeping an eye on them to ensure their safety. When the vampire attacked Simon, Isabelle came out and killed her. Simon, who was still flustered about his lack of memories of Isabelle, was displeased and called her out for her constant intervention in his life and choices. Isabelle, distressed by his reaction and words, then told him that she might not want to know the new him anyway, given how he'd been acting, and that she was there for the task assigned to them, not for him. She once again left, leaving their relationship in an even worse note.
Clary instantly noticed how hurt Isabelle truly was over Simon's continued rejection and overall treatment of her. During a visit at the Academy, Clary and Jace made Simon aware of this, who then gathered up his courage and sent her a letter through Jace. Isabelle returned the letter unopened some time after.
Two months after, Izzy went to the Academy with her father, who was giving a lecture to the students about responsibility. As part of the exercise, she tried to coax the students into indulging themselves with indecent behavior before the end of the school year. Most of the students willingly followed, and thus failed Robert's moral test, while Simon, along with Beatriz Mendoza, outright refused to get involved, though this was initially simply to avoid Isabelle. Isabelle was incredibly proud of Simon. Through it all, Isabelle was an unwilling participant in Robert's mind games, and she asked Simon to stay while she confronted her father about it. Robert then tried to apologize in his own way, telling them that she and her siblings were the ones he loved unconditionally.
At the Academy's party, Izzy approached Simon, who then apologized for his behavior, though in a less passionate manner that he had tried to in his letter. Isabelle then made it clear that she had forgiven him, and she was open to the idea of getting to know each other again—even dates. Shortly after Simon returned to Brooklyn for the summer, the pair went on three dates, two of which Simon ended with awkward handshakes. On the third, they went on a double-date with Jace and Clary; the group was attacked by demons, and the three of them went on a road trip—without Simon—to hunt down whoever sicced the demons to them. When they returned shortly before Simon was set to return to the Academy, neither called each other, which they both took as subtle rejection.
Isabelle then asked Helen to give Simon a letter asking for permission to visit him because she had ambushed him with her appearances in the past. In reality, Izzy was already at Idris, and when Simon told Helen to tell her that he wouldn't mind, she revealed herself. She told him that she wasn't ready to give up on them just yet, and decided that they could go on a date in Alicante—neutral ground where they wouldn't be pressured by preexisting memories of the place. Isabelle took him to Diana's Arrow to help pick out a weapon—an idea she got from Jace. When Simon seemed visibly uninterested, she got pissed. They later got into an argument about faeries, then later about their non-issues with Simon's missing memories, after which Izzy stormed out of the store.
Simon followed her, and the pair made up, agreeing to stop trying too hard and pretending to be like Jace and Clary. The pair went to an isolated inlet by Lake Lyn then for another date—an impromptu picnic that finally went well. There, Simon told Izzy that she barely remembered things about their past because he felt that the most important bits of his past were the hardest to access. She also told him that she was slightly envious of his amnesia, saying she still hoped to forget about Max's death and that he had helped her after his murder. When Simon suggested returning to the Academy, Isabelle confronted him about why he still hasn't made an attempt to kiss her when he clearly wanted to. He told her that the idea of losing himself in her scared him, and Isabelle reassured him by saying that they'd be taking the leap together, and he finally kissed her. They then attended Helen and Aline's wedding together.
The night before Simon's Ascension, he snuck out of the Academy with Clary and Portaled back to New York. Simon found his way back to the apartment he shared with Jordan where Isabelle found him. They went back to Magnus' deserted apartment, where she reassured Simon that she knew he would survive his Ascension, but backing out wouldn't make him a coward or any less the hero she knew him to be. The couple then slept together and spent the rest of the night together, before Simon made his way back to the Academy the next morning. Along with the others, Isabelle went to the Council Hall to watch Simon's Ascension. When Simon regained his memories during the ritual, his memories came flooding back, and most of it had been filled with moments with Isabelle. Later, Isabelle went to the London Institute with Simon for his roommate, George Lovelace's, funeral.
When her mother stepped down as head of the Institute, Isabelle made it clear that she did not want the position because she intended to travel. Both she and Alec were not interested, and the members of the Conclave voted for Jace and Clary to take up the position as co-leaders. When Simon proposed to her in August 2012—a spur-of-the-moment decision after fighting off a demon—around three years into their relationship, Isabelle said yes and told Simon that she wanted an engagement party in two days—in time for Max's birthday—which Clary managed to pull off.
Isabelle initially shared the Lightwood family's snobbish attitude toward mundanes and Downworlders. However, after meeting Clary and Simon, her outlook changed, first for them and eventually for all other mundanes and Downworlders.
She is very confident in herself and her abilities. She has a great sense of style and is very fashionable. For a time, she was also somewhat promiscuous. She can be vain and somewhat narcissistic, but also slightly insecure, and at times even self-conscious about her height. Despite initially displaying a haughty and nonchalant attitude toward others aside from her family, she actually hides beneath it a distrustful and fragile heart.
Isabelle also possesses a fiery temper which numerous characters are victims of. In spite of her mature and refined nature, she has a habit of throwing temper tantrums and locking herself in her room when things go wrong, flinging objects at people when they intrude on her solitude. While Clary at first finds Isabelle's abrasive nature disquieting, she soon grows to like her when she comes to know her warm side.
Isabelle is very loyal to her family. She is a fiercely loyal friend but is volatile and prone to mood swings. Isabelle is described as very flirtatious. She dates many different boys, especially boys that her parents won't approve of. She later reveals that she does this to draw attention away from her brother Alec, who is gay, so that their parents won't become suspicious of him. This begins to show a much deeper and loving side of her that is often only revealed when around her family. She loves her brothers, being particularly close to Alec, and defends them passionately when threatened. Her brother, Max's, death hit her particularly hard, feeling that she failed him, because she ignored him when he said something was wrong. Her grief led to her skipping his funeral as she felt that she didn't deserve to go.
Isabelle is later revealed to be cautious when it comes to love. This stems from her mother telling her to never trust men, because they will always hurt her. Though at the time she didn't understand the significance of it, she later revealed that she doesn't know how to truly love, though her passion for Simon certainly seems to be opening her up. She is baffled, looking at her brothers, to see them giving themselves to love. She doesn't understand how they can open themselves up to such sadness.
Isabelle also rather likes cooking but is not very good at it. Her mother, Maryse, was always a good cook but she never taught Isabelle, fearing that she might be relegated to the kitchen forever, instead of being a great Shadowhunter she eventually grew to be.
Jace once described Isabelle as one of the best Shadowhunters he knew. She loves her life and the fight against demons. She greatly enjoys demon hunting. She is also often the 'bait' for demons that she, Jace, and Alec are hunting. She is a very free-spirited girl that enjoys partying, flirting, and clothes.
Isabelle is also very confident in her looks, this is in stark contrast with her brother Alec who isn't confident in his own skin. She frequently uses her looks to achieve her goals, wielding them in everyday life like she would her whip in a fight.
Isabelle is described as incredibly gorgeous despite the scars left on her skin from the Shadowhunter runes. She has long, ink-black hair that goes down to her waist, and dark brown-gold flecked eyes that are usually mistaken for black. She shares the same slender eyebrows, pale, high-colored skin as her brother Alec. She is said to greatly resemble her mother, so much that Jocelyn Fray mistook her to be her mother when they first met. She is quite tall standing at 5'9", being taller than most boys, and very slim. Despite her looks, Isabelle greatly envied Clary, and other girls like her who were small and petite, in the past; though she is happy with her looks, she felt it a hassle to be taller than most boys.
Isabelle is known to be fashionable and usually wears a dress; Clary once even stated that she rarely sees Isabelle in anything other than dresses, though she is known to also wear casual clothes. Isabelle also has an inclination towards very high heels.
Skills and abilities
- Nephilim physiology: Being Nephilim, Isabelle possesses a variety of enhanced physical and mental abilities granted to her by the blood of Raziel in her veins and also by the angelic Marks of the Gray Book. She also has the power to perform tasks unique to their species, such as the ability to use and call on the power of angels for their seraph blades. This includes enhanced strength, agility, stamina, and coordination, which only improves over time and practice.
- Runic magic: Due to the angel blood in their veins, all Shadowhunters are able to apply runes on their skin without any real danger. These Marks, in turn, give varied effects that serve to benefit the wearer.
- Lightwood family necklace: Isabelle inherited the family necklace. The ruby pendant of the necklace also serves as Izzy's Sensor, pulsing bright red in the presence of demons.
- Electrum whip: Isabelle uses her trademark silvery-gold whip as her preferred choice of weapon. The whip was a birthday present from her father when she turned twelve. She shows a high level of skill and proficiency wielding the whip.
- Daggers: Isabelle has also been shown to include a pair of daggers in her arsenal.
- Other basic Shadowhunter gear, including: steles, seraph blades, and witchlight.
Isabelle always had difficulty with commitment. Ever since her mother told her to never trust men she guarded herself from them with a string of lovers that were all troublemakers that would irritate her parents. It took Isabelle a long time to realize how she was affected by her mother's advice.
When Simon first came to the Institute, he was immediately starstruck by Isabelle, thinking that he finally found someone that could help him get over Clary. Though at first she shows little interest in him in any way other than flirting, he accompanies Isabelle, her brothers, and Clary to Magnus Bane's party. The two dance together, and Isabelle, though intoxicated, worries about him when he was turned into a rat.
When Simon is attacked by vampires, Isabelle is deeply distressed by it and threatened to kill Raphael if he didn't explain what happened to Simon.
Isabelle and her family went on a trip to Idris when Forsaken attacked them. Simon was forced through the Portal and the two of them stayed in Idris together for a short period of time. During Simon's imprisonment in the Gard, Isabelle often brought him blood and signed the card with multiple XOs.
After the death of Isabelle's brother Max, Simon was the only one that she opened up to, insisting that Simon would sleep with her in order to feel better.
In City of Fallen Angels, they casually date until Isabelle finds out he is also dating Maia Roberts and dumps him. However, she is unable to shake her deepening connection with him.
In City of Lost Souls, they spend nights together at Magnus', with Simon helping Isabelle sleep—something she still has a hard time doing alone—often lulling her to sleep with his stories that she pays attention to. Isabelle even lets Simon drink her blood. The pair grew closer, though she remained reluctant to accept she may actually be in love with him.
In City of Heavenly Fire, they finally admit their feelings for each other. Isabelle is distraught when Simon's memories are taken away, and she and Magnus finally manage to get him back a few months later, to her relief and happiness.
|“||I’ve only ever trusted a few people in my life. Really trusted. My mother, Alec, Jace, and Max. I lost one of them already. Clary’s the only reason I didn’t lose another.||”|
Isabelle is not very open to Clary in the beginning since she finds it difficult to make friendships with girls her age. However, after Clary finds out about Alec's sexuality and keeps it a secret Isabelle warms up to her just a little. Their relationship during City of Ashes and City of Glass isn't progressing very much since Isabelle believes that Clary is the reason Jace is so miserable. However, after the events of these two books, Isabelle and Clary come closer with Isabelle even making jokes and witty comments about Clary's relationship with Jace.
|“||I admit I do get a bit protective of my big brother. He always protects me. (...) He's one of the best things in my life...||”|
Alec is Isabelle's brother. Both are very protective of each other.
Izzy was aware of Alec sexuality from a young age, long before he came out. Isabelle, however, never talked to him about it, out of respect for his privacy and knowing that it would make him feel uncomfortable. She is always concerned about Alec's emotional well-being and his love life. Wanting Alec to be happy and open about his sexuality, Isabelle was quick to try and set him up with Magnus. She was also one of the first to notice that two were seeing each other before they made their relationship public. When it did become public knowledge, Isabelle tried to protect him from other people's negativity and stood by her brother whenever she could.
Robert and Maryse Lightwood are Isabelle's parents.
|“||Maryse and Isabelle exchanged a speaking look. She and her mother had always been able to communicate like this. Isabelle thought it was because they were the only girls, and special to each other.||”|
Isabelle grew up having a very close relationship with her mother. When she was young, Maryse opened up to her about Robert's affair, venting and teaching her at a tender age not to trust men and to be a strong and independent woman.
Isabelle held some deep-seated resentment towards her father due to his extramarital affair and his general distance, particularly when it came to Alec. This came to a blow in 2007 when Isabelle confronted him about it in the heat of an argument. After the Dark War, Robert tried to take steps to make amends and fix their relationship until, finally, Robert tried to sincerely tell Isabelle how much he loved them and hoped to make it up to them.
|“||Jace's hand was suddenly damp where she was holding it, and he realized she was crying, her tears splashing down crying for him, because she loved him; even after everything that had happened, she still loved him.||”|
Jace is Isabelle's adoptive brother. Jace and Isabelle truly act like brother and sister and he considers her family. He makes fun of her often but is also affectionate of her. He and Alec often make fun of her terrible cooking. When Jace first came to New York with them, though, it took a while for Isabelle to accept him, but they eventually bonded over their passion for fighting.
While Jace was being trapped by the Inquisitor, Izzy strongly protested that Jace wasn't Valentine's pet. When Alec said instead that Jace was evil, Isabelle was furious and refused to talk to her older brother until she learned that he was lying to deflect suspicion from himself and had rescued Jace. Later on, after he was freed from |Sebastian, being stabbed by Glorious, She and Alec sat with him for days to make sure he'll recover. When he regained consciousness, the three shared a very touching moment together.
Max is Isabelle's 9-year-old brother. She fell into a brief depression when he was killed by Sebastian, thinking that he would still be alive if she just listened to him. After his death, Isabelle has locked herself in her room all day and hasn't been talking to anyone. When Alec and Jace tried to comfort her, she refused to let them in. Although she still blamed herself, she had eventually forced herself to get out so that she could avenge his death by killing Sebastian. She cares deeply about her brother and even helped arrange her engagement party in two days so it would be on his birthday and she could feel as if he's there with them too, since it was about 5 years after his sudden death 
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Isabelle's name means "My God is a vow" in Hebrew.
- Isabelle is allergic to tulips.
- Isabelle was fascinated by the history of weapons as a child. She spent hours reading about close-range combat in the Institute's library.
- Like many other Shadowhunters, Isabelle never wanted to have a parabatai.
- Isabelle's middle name, Sophia, is also the name of a Lightwood from the 1800s—Sophia, who also happens to be the wife of Gideon Lightwood, after whom the middle name of Isabelle's brother Alec may have been adapted from.
- Isabelle was named after Cassandra Clare's grandmother.
- A widespread theory among some readers was that Isabelle wasn't really Robert's child, primarily due to her dark brown eyes while both Robert and Maryse have blue eyes; a few even went further and believed that she could be the child of Maryse and Valentine. The theory was later debunked by Cassandra Clare herself.
- ↑ Official Clave Files in the City of Bones 10th Anniversary Edition
- ↑ Sizzy height — Cassandra Clare on Twitter
- ↑ 3.0 3.1 City of Fallen Angels
- ↑ 4.0 4.1 4.2 4.3 City of Bones
- ↑ 5.0 5.1 City of Ashes
- ↑ City of Glass
- ↑ City of Lost Souls
- ↑ 8.0 8.1 8.2 City of Heavenly Fire
- ↑ Welcome to Shadowhunter Academy
- ↑ The Lost Herondale
- ↑ The Whitechapel Fiend
- ↑ 12.0 12.1 The Evil We Love
- ↑ Pale Kings and Princes
- ↑ Bitter of Tongue
- ↑ Welcome to Shadowhunter Academy
- ↑ 16.0 16.1 A Long Conversation, a Lady Midnight extra
- ↑ Son of the Dawn
- ↑ What to Buy the Shadowhunter Who Has Everything
- ↑ [A Long Conversation]
- ↑ A History of Notable Shadowhunters & Denizens of the Downworld
- ↑ "Isabelle doesn't want one." — Cassandra Clare on Tumblr
- ↑ "Isabelle doesn't want one." — Cassandra Clare on Twitter
- ↑ "She never wanted one. Not everyone does." — Cassandra Clare on Twitter
- ↑ "Max and Isabelle are named for my grandparents." Cassandra Clare's FAQ: Name
- ↑ "About Isabelle’s eye color" — Cassandra Clare on Tumblr