SPOILER WARNING: Plot details follow. Caution is advised!

I've decided to grow up, remember?

–Isabelle, Major Arcana

Isabelle "Izzy" Lightwood is a Shadowhunter and the current head of the New York Institute. She is the only daughter of Robert and Maryse Lightwood, is the sister of Alec and Max, and is the adoptive sister of Jace.


Early life

And what's the rule when our team goes into battle? Three go in. Three come out.

–Isabelle, Alec, and Jace's saying in their youth, A Heart of Darkness

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Born the middle child and only daughter of Maryse and Robert Lightwood, Isabelle is the sister of three brothers: the eldest, Alec, the youngest, Max, and Jace Wayland, who was taken in by the family when they were young. Raised in the New York Institute, Isabelle trained side-by-side with her older brothers and forged a close bond with them. Isabelle was sure about not wanting a parabatai since she was young,[1] and there was a time when she wanted to become an Iron Sister, before she realized it would have meant having to swear off of boys.[2]

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Just before Jace and Alec decided to become parabatai, Alec came to her about his doubts, and she realized that it was because Alec had fallen in love with Jace. Isabelle told Alec not to abandon the bond, reminding him that what they shared may come once in a lifetime, but someone else may come along to love him the way he loved Jace, and this proved to be enough to convince Alec to go through with the ceremony.[1]

New friends

One evening, Jace managed to track a shape-shifting demon's activity to the Pandemonium. Isabelle decided to go in disguise, with an all-white outfit and a platinum blonde wig. Once inside, Isabelle distracted the other demons while Jace confronted the one that was peddling mundane blood. She managed to keep them busy until the fight broke out.

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When Jace brought Clary Fray to the Institute, Isabelle was with her when the latter woke up. Isabelle even lent her some clothes after Clary's had to be burned.[3] Later, her mundane friend Simon Lewis was also welcomed into the Institute, and Isabelle volunteered to look after him and cooked him breakfast. She also briefed him about the Shadow World and the dangers Valentine Morgenstern and the Circle posed for all of them.

The group soon realized that Clary may lead them to the Mortal Cup; for this, they helped her retrieve her memories and save her abducted mother. Outside the Silent City, Isabelle, again volunteering to stay with Simon, was flirting with Simon and was alone with him by his van when she heard sounds. She left to investigate, and Simon was gone when she returned. She told the others, and when everyone rushed back to the van, two vampires revealed themselves to be Simon's abductors, negotiating for the Cup.[4]

To contribute to Simon's rescue, Isabelle contacted the Seelie Meliorn, with whom she maintained a sexual relationship with—a connection she often used to her advantage to gather intel. In this case, Isabelle knew that Meliorn was also sleeping with the vampire Camille Belcourt and that he might be sneaking into the Hotel Dumort to do so. After getting the information she needed, she immediately told Alec and Jace.

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She and Alec served as the distraction, going into the entrance she learned from Meliorn, while Jace and Clary went to a more direct route in hopes of finding Simon sooner. She and Alec managed to keep the vampires occupied and beat most of them in battle, and they eventually regrouped with Jace and Clary. Together, they all found Simon with Raphael. Raphael went on to help the group escape.[5]

Family's honor

When Isabelle's parents returned from their trip to Idris,[6] she and Alec learned that their family was under the Clave's scrutiny. She discovered from her father that in order to reaffirm the Clave's trust in their family, a tremendous sacrifice would have to be made. She overheard Maryse's insistence that Alec be married off to a Shadowhunter woman for a political alliance and, disapproving, warned Alec about it. Robert told her that she would be playing the part of a diplomat because of her ties to the Seelies, particularly Meliorn, which Maryse later told her was because she doubted she would be capable nor willing to accept the tough decision for their family.

Isabelle bidding Meliorn and her old lifestyle goodbye.

Maryse later apologized for her choice of words and tried to make Isabelle see it from her point of view, who struggled with being simultaneously their mother and commander. She related her own experience in her youth to Isabelle's but did not take back her opinion that she believed Isabelle wasn't ready for the responsibility. Deciding to put her family ahead of herself, Isabelle took her mother's words to heart and began a process of self-transformation, beginning by changing her manner of dressing, completely stashing her clothes away, and ending her relationship with Meliorn.[7]

When Alec proposed to Clave envoy Lydia Branwell, who was sent to take temporary control of the Institute, Isabelle objected, worried that he was forfeiting his happiness. Her dislike of Lydia further grew when she arrested Meliorn, believing he had information on Valentine's whereabouts. With the help of Jace, Clary and other Downworlders they managed to recruit, Meliorn was rescued en route to the City of Bones where he would have been tortured and possibly killed. Before Meliorn escaped with Jace and Clary, she gave him a kiss goodbye.[8]

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Because of her connection to Meliorn, and from statements by Raj of the ambush on the team accompanying Meliorn, Lydia became convinced that Isabelle was involved in his escape. She was arrested for high treason, and the esteemed Inquisitor Imogen Herondale arrived very shortly after for her trial at the Institute. Alec was able to recruit Magnus Bane to defend her. After listening to Isabelle's statement, Lydia decided to drop the charges. During his defense statement, Magnus pointed out that Isabelle was only arrested because the Clave wanted the Cup. The Inquisitor later confirmed this herself and and stated that if the Cup was not returned to the Clave within 24 hours, Izzy would be stripped of her runes and exiled. Jace and Clary later returned with the Cup, having completed their mission with it, freeing Isabelle of her charges.[9]

Isabelle immediately began planning Alec and Lydia's wedding, excited to work on something new for the Institute; despite still not being convinced that Alec was happy with his decision, she supported him. Wanting to throw a bachelor party for him, she decided to consult a potential expert on the matter: a mundane, which left her with little option aside from Simon. Simon's description of it made Isabelle realize that what Alec needed was for him and Jace to make up, which she managed.

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She invited Magnus to the wedding, even though she did not expect him to come. Isabelle was happy to see him arrive, and when Alec finally decided to choose his own happiness and essentially stopped his wedding by kissing Magnus in front of everyone, Isabelle was the first to run up to him to express her pride, fully supportive of him despite Maryse's apparent displeasure.[10]

After the wedding, the group found out Hodge Starkweather stole the Cup and was on his way to hand it over to Valentine. Isabelle, Clary, and Simon sought out Camille, who was being held the Dumort, for the Book of the White, which they needed to wake Jocelyn. Isabelle distracted Raphael while Clary and Simon snuck into the room where Camille was being kept. They were caught, but before the vampires of the clan could kill them, Isabelle was able to save them and get them out of the hotel. Later, at Camille's home, Isabelle and the others were held down by Valentine's men, convincing Jace to join Valentine to keep them from harm.[11]

Saving Alec and Jace

When Alec showed signs of stress and frustration over Jace's departure, Isabelle was the one who suggested he take a break. She defended Jace from the new Head of the Institute, Victor Aldertree, a representative sent by the Clave to turn the Institute around, when he declared Jace a traitor. Despite Aldertree banning the group from the hunt for Jace, they continued to do everything they can to get him back.[12]

When Valentine began sending his followers to kidnap fighters from fight clubs and dojos, in search of strong candidates for his army, Isabelle and Alec were among those sent out to catch a Circle member for information on Valentine. Isabelle was torn between wanting to help Clary and backing her brother, who wanted nothing to do with Clary and was partly blaming her for Jace's actions, but comforted Clary before they left.

At one of these dojos, Isabelle challenged Mark, one of the known fighters of that club. She later used the shape-shifting rune to turn into him and successfully lured a Circle member to them. Before she or Alec could get to him, he slit his own throat, choosing to die than give up Valentine. Upon losing this Circle member, Alec grew even more frustrated and discouraged about finding Jace. When Jocelyn approached them with a way to find Jace using adamas, Isabelle was quick to object after being told of the risks. Isabelle had no sway, however, as Alec had already decided, determined to try anything to find Jace.

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Alec went through with using the adamas and fell into a comatose state,[13] later worsening, and almost killed him. Isabelle stayed by his side while Magnus tried to heal him; his efforts were for naught, managing only to keep him stable enough to survive for a couple of hours. They learned that they needed Jace for Alec to fully recover. Luckily for them, Clary and Jace had just escaped Valentine's ship, and though they were separated, Jace contacted her. She immediately told him about Alec's state, and they made plans to meet at Magnus's loft with Alec.[1]

When Aldertree refused to let Isabelle and Magnus take Alec out of the Institute, under the guise of seeking treatment in Idris, they used a shape-shifting rune on an unconscious Raj to disguise him as Alec when they snuck him out. Aldertree was quick to catch on, and when he informed her that Jace was in danger, she begged him to give her access to a Portal so she could save Jace—and subsequently Alec. In exchange, Isabelle agreed to guarantee Jace's surrender to the Clave. Isabelle succeeded and managed to hold back the werewolves looking to kill Jace, and they managed to get him to Alec in time to save him. Immediately after her brother was awakened, Aldertree arrived to arrest Jace.[1]

Yin fen

When the Institute was attacked by a demon sent by Valentine, Isabelle was possessed by the demon. Feeding on her anger, it made her attack Alec. To get the demon out of her body, Clary stabbed her in the back and killed the demon once it had left her body.[14] This left her with a wound which later became infected, affecting her overall physical condition.

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Despite the injury, when she heard of an upcoming mission to the Adamant Citadel, she got excited, eager to at least partly fulfill her previous dreams of becoming an Iron Sister. She requested Aldertree to allow her to lead the mission, but Aldertree examined her wound and saw the infection. Before allowing her, Aldertree gave her yin fen to help speed up her healing; the salve was pleasurable to Isabelle, and she soon found herself addicted to the substance. She did not immediately realize the dangers of the drug and was grateful to Aldertree for it. She then asked him to allow Clary to go with her on the mission, but was instructed to spy on her and report back to him in return.[2]

Isabelle fails her purity trial.

When they arrived at the Citadel's land, they were prompted to undergo a purity trial to be given permission enter the Citadel's stronghold. While Clary passed the trial, the water turned black and bubbled violently when Isabelle took part. Sister Magdalena deemed her blood tainted with demonic impurities, meaning she would not be allowed inside the Citadel. She told Clary to go on without her, knowing that they still need information on the Soul-Sword. Sister Magdalena, having figured out that she'd been using yin fen, told her about the drug's demonic true nature.

Outside the Citadel, Isabelle listened in on a conversation between Clary and Sister Cleophas and heard about the strange Sun rune. When they returned to the Institute, Isabelle confronted Aldertree about the yin fen and her failed purity trial, and Aldertree only apologized in response, saying he only wanted to help her. Despite her apparent growing addiction to the substance, Aldertree enticed her with another case, pleased to seemingly have her wrapped around his finger for the drug. Despite wanting the case, she decided to keep what she'd found out to herself.[15] Further taking advantage of her fragile state, he tried to ask her out, but Isabelle declined.[16]

Isabelle was quick to experience the symptoms of withdrawal from the yin fen—her tremors, sweating, chills, agitation, and a pale complexion—and sought to find a new source, with Aldertree in Idris and the yin fen in his office gone. Desperate for her fix, she went to the Hunter's Moon to find a Downworld drug dealer. She found the warlock Rufus and asked him for yin fen. When she was caught speaking to the dealer by Magnus, Isabelle pretended to be investigating the Downworlder drug trade. Through him, she found out that users of the drug would sometimes go straight to the source: vampires, for their venom, which was the main component of yin fen.

When she was unable to convince Simon to bite her, Isabelle went to a vampire den. Outside, she was surrounded by a number of vampires, including Eloise, who were more than willing to bite her. Before the vampires could kill her, Raphael stepped in and sent them away. She began convulsing in pain from the withdrawal and she begged Raphael to bite her, just once, to make it go away.[17]

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Isabelle quickly learned that while getting vampire venom directly from the source had a stronger effect, it wore off much faster. When she experienced the symptoms of withdrawal again, in time for Maryse's visit and Max's Rune Ceremony party, she called for Raphael, who was unable to resist her request for more venom as he was growing equally addicted to her Shadowhunter blood.[18]

Isabelle and Raphael began to spend more time together. They learned more about each other, and Raphael even introduced her to his last living relative, his sister Rosa, though it became clear that they were both unethically enjoying the high of Raphael feeding on her. At a Downworld Council meeting, Meliorn recognized the smell of Isabelle's perfume on Raphael. Magnus found out and realized that Isabelle had lied about working on the Downworld drug trade and had gone to a vampire for venom. He immediately told Alec, who immediately confronted them at the Hotel Dumort, even catching them in the act of feeding. Alec punched Raphael, stopping only when Magnus intervened, and dragged Isabelle out with him, but Isabelle refused to leave, retorting that Raphael had been there for her while Alec didn't even realize that something was wrong with her.[16]

Isabelle returned to Raphael, who stated that he truly had feelings for her. She tried to kiss him, but he revealed that he was not interested in sex—that he had always been asexual. He then secretly hid her phone before stepping out, to keep her from finding out that the Seelies and vampires planned on killing Clary. She eventually found her phone and saw messages from Alec about Valentine's attack on the Institute and rushed there to help, killing four Circle members before they could get to Alec and Aldertree. In the aftermath of the Soul-Sword's destruction, Isabelle was glad to see that Raphael was alive, but let him know that she never wanted anything from him ever again.[19]

Road to recovery

Now with Alec's support, Isabelle tried to get the vampire venom out of her system. She hid out in her room and everyone, except Alec, was told that she had the flu. The pain and intensity of her venom withdrawal became so intense that she eventually caved and left the Institute during Alec's absence. She went to the Dumort to ask Raphael for venom again, apologizing for their last encounter, but lashed out and almost stabbed him when he refused. She left then and proceeded to the nearest vampire den.

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Outside the den, Isabelle was attacked by the demon that Alec and the others had been hunting—the Greater demon Azazel. Before he could kill her, a Shadowhunter arrived and drove him away. Isabelle was knocked unconscious and was taken to his apartment. When she woke up, he introduced himself as Sebastian Verlac, a Shadowhunter from the London Institute who'd gone AWOL in search of a cure for his own addiction to yin fen—which he'd found. He gave her a drop of medicine from a root extract, which he discovered would help with the withdrawal. Though she meant to leave, he convinced her to stay for a day to get the venom out of her system, as the medicine's effect only lasted a short while. Upon his request, she also called Alec to let him know she was safe.[20]

By the next morning, Isabelle had fully recovered with Sebastian's help. In gratitude, she invited him to the New York Institute with her.

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Simon then came to her requesting help on dealing with Raphael, thinking her relationship with him would provide some insight. Isabelle's took him to the home where Raphael's sister Rosa was staying and had him take a photo with her—to answer Raphael's threats with his own. During their visit, Rosa noted that they looked good together, before they denied being a couple.

Their plan backfired and only angered Raphael, but ultimately Simon's Daylighter status protected him. Meanwhile, Simon, upon learning of her recovery from yin fen addiction, planted the idea that she should attend a mundane recovery program or group meetings for addicts, as they greatly helped his mother with alcoholism. She refused at first, but by the end of the day, she considered the idea, and Simon promised to send the information to her.[21] She eventually began to attend these meetings,[22][23] where the mundanes believed that she was referring to heroin.[22]

Training Max

You'll have four training sessions a day: demon strategy, weapons, combat, and endurance. Breakfast starts at five. If you are late, all you'll have is a cold bran muffin.

–Izzy to Max, Those of Demon Blood

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Some time after Max's Rune Ceremony, he was sent back to the Institute for training. Alec appointed Isabelle as Max's personal tutor, encouraging and convincing her that she was ready despite her recent struggles. Max's overconfidence and eagerness to prove himself proved deadly when he followed her on her field mission, where she was tracking a Downworlder that was deruning and killing Shadowhunters. While she was distracted, the killer, Kaelie, took Max to kill him, but Isabelle, with the help of Raphael and Meliorn, managed to save him.[22]

Max's stubbornness continued as he refused to do the petty training tasks Isabelle was giving him such as tracking a bird, convinced that he was already a good tracker, and informed her that he had been approved by the Clave for his first mission. Isabelle freaked, still worried and overprotective of her brother especially after his near-death encounter with Kaelie. She confronted Alec about it, who reminded her that they were his age when they began receiving orders. Later, she enlisted Simon's help in training Max. Simon was able to alleviate her worries, reminding her that it was what Max, like she, was born to do.[24]

Isabelle hadn't been too far off about worrying for Max, because she found Max unconscious and injured in her room at the Institute later that evening. Isabelle stayed by Max and her family throughout the Silent Brothers' treatment of him, and protecting him from any more attacks from Jonathan, Clary's demon-blooded brother. She was incredibly relieved when he finally regained consciousness, but was later wrecked by the discovery that the man she'd trusted as Sebastian was in fact Jonathan and had been the one responsible for Max getting hurt.[25]

Izzy striking at Jonathan.

You didn't seem to have a problem when you took a run at my baby brother. I trusted you when I was at my weakest! At my lowest! I brought you into my life into my family and you betrayed me!

–Izzy to Jonathan, Hail and Farewell

Isabelle, Clary, and Jace went on the hunt for Jonathan, but only found the corpse of the real Sebastian Verlac, whom Jonathan had been impersonating the whole time. When New York City was warded by the warlocks under Magnus's guidance to keep Valentine and Jonathan within the city, they tracked Jonathan to a mundane cemetery, where he set up a trap to keep them distracted while Valentine escaped to Alicante. They battled the Forsaken turned by Valentine and Jonathan, and later, Isabelle joined Jace in the fight against Jonathan. Together, they managed to kill Jonathan, avenging Max, Sebastian, and herself.[26]

Weapons master

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Shortly after Valentine's death, Isabelle was named the new weapons master of the Institute. With this position, she oversaw Clary's choosing of her signature weapon. When Clary chose a pair of kindjals, Isabelle commended her decision, telling her that it complimented her fighting style, where she noted that she used her left arm for balance, and dual-wielding would allow her to use that to her advantage.[23] Her new position also gave her access to the equipment she needed to fix her demon-detecting ruby, which had been destroyed in the encounter with Azazel.[27]

When Luke came to the Institute and told them about a recent murder case that involved a possessed mundane, Isabelle went with Jace and Alec to ask Catarina Loss about the mundane at their workplace, St. Ambrose Hospital.[23]

Dating Charlie

After speaking to Catarina, Isabelle bought a snack from the vending machine and interacted with Dr. Charlie, who helped her get the candy she bought that got stuck in the machine. Though she didn't plan to give it, the doctor asked for her name and she obliged.[23]

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The two met again some time after while Isabelle was staking out a party thrown by Morgan Young, another target of the Owl, with Jace and Clary. This time, Charlie asked for her number, and, wanting to focus on watching Morgan, she agreed. She and Clary lost sight of her and Morgan ended up becoming possessed. Isabelle went after her when she ran and was able to capture her, after which she and Clary took her to the Institute where she was imprisoned to keep her safe.[28]

On a different case, Isabelle and Clary went after a rogue vampire who'd recklessly caused a mess after feeding from a mundane. After battling and killing the fledgling—the mundane that the rogue vampire had fed on and Turned—they heard screams from the rooftop and quickly responded. Isabelle recognized the voice as Raphael, and she and Clary tore the door down to save Raphael from the sunrise. On a hunch, Isabelle followed him back to the Dumort and saw that he was trying to cover his tracks. She was quick to put things together and realized that the rogue vampire went after him for revenge. Raphael explained to her his motives behind experimenting on the girl; disappointed in him, Isabelle told him that she wouldn't report him to the Clave but he must leave the city.[29]

The mundane Charlie was eventually able to convince Isabelle to go on a date with him, and though she almost backed out at the last minute, Clary convinced her otherwise. During the date, Isabelle had fun but, hen pressed for information, found herself lying about her background. From the pieces of half-truths she could tell him, she ended up letting him believe that her family ran a jewelry business. Though the pair intended to have drinks after their dinner, Isabelle's ruby lit up, notifying her of a demon nearby. She looked for it, and the demon—which had tracked Clary's scent through the dress she had borrowed from Clary's closet—attacked her, but Isabelle was easily able to kill it. Charlie found her in the alley with a small cut on her head and took her to the hospital so he could give her stitches.[30]

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When Maryse, who had just been deruned, arrived, Isabelle kept her company and succeeded in making her feel comfortable enough to be honest about her true feelings about the situation while alone with her. Isabelle reminded her that she wasn't alone and had four kids who loved her. She and Alec made plans to take Maryse out that night, and when Maryse agreed, she asked Isabelle to bring Charlie. The night at Hunter's Moon started out relaxed, and when Luke arrived, she and the others left them alone at the table to catch up. She spoke with Simon, who'd been guarding Maia at the bar, and gave him a small kiss on the cheek for his kind words.

Unbeknownst to them, the rogue vampire Heidi who was obsessed with Simon saw the moment and mistook Isabelle to be his girlfriend. Heidi confronted her outside the bar's restroom. After taking her down, she demanded for her identification as a representative of the Clave before Simon arrived and explained their situation. Isabelle only agreed to let her go because of Simon's pleas. When she stepped outside, Charlie saw blood on her, which she brushed off as a nosebleed. This distracted Charlie and had him follow her, inadvertently saving him from the Owl.[31]

They learned from Clary that Jace was the Owl, and from Magnus that Jace had been possessed and was being controlled by the Greater Demon Lilith. They devised a plan to trap Jace somehow to buy them some time to figure out how to save him, and Isabelle recommended the Malachi Configuration, having read about it since she had been appointed as the weapons master. They asked for help from Jace's grandmother Imogen and were ale to sneak the Configuration out of the Armory, after which they heard from Imogen that Jace was in Idris, at the Cemetery of the Disgraced. They surrounded him at the Cemetery and trapped him in the Configuration, and Clary later used a Portal rune to send them to Magnus's loft, giving them time to save Jace while she let herself get apprehended by the guards.[32]

Around this time, Isabelle ended things with Charlie, having grown tired of lying to him about herself and the life she led.[33]

Jace begs Izzy to kill him.

Magnus found a way to attempt to save Jace by using his and Alec's parabatai connection to reach the real Jace. Isabelle volunteered to go into Jace's mind with Alec, not willing to see Alec in danger again. Once in, Isabelle found Jace being forced to see his loved ones—she and Alec, and Clary—disappearing and dying in his mind, a form of mental torture to let Jace feel defeated. She and Alec were separated by a barrier, and Isabelle found a sliver of Jace's soul, in the form of his younger self. She sang to him the French song À la claire fontaine to remind him of their childhood and managed to get him to trust her. Together, they found Alec and the real Jace, who then asked them to kill him to prevent him from doing any more of Lilith's bidding. Isabelle and Alec refused and were moments away from saving Jace, having convinced him to leave his mind prison with them, only to be interrupted by the arrival of Lilith breaking the connection and taking Jace's body.[34]

Izzy snapping Simon out of his feeding frenzy.

While Magnus looked for another way to save Jace, Isabelle and Alec worried about Clary but were constantly blocked by the Council from finding out what was happening to her. Later, Jordan Kyle, a Praetor assigned to Simon, came to the Institute asking for her. He told her that he was missing and asked her to track him with his shirt. They tracked him to his old house, in time to find him feeding on his sister, Rebecca. She begged Simon to stop and pulled her away from him, and watched as Simon's mother frantically turned Simon away in fear.[35]

She and Simon took Rebecca to the hospital, and Isabelle stayed with him for support. Once he was done speaking to his sister and mother, Isabelle received word from the others and told Simon that Lilith had Clary. They went to the building where Lilith moved and devised a plan: Alec set off alarms to lure out the mundanes who had no idea that the building was being used by Lilith, and to make Lilith's disciples respond to the invasion. She and Luke faced off against Lilith's disciples, agreeing to try and not kill any of them as they were just possessed and could still be restored. This bought Simon time to get directly to the top floor, to Lilith and Clary, without the disciples getting in the way. They then witnessed the disciples being freed from Lilith's control after Simon managed to banish her back to Edom.[33]


Isabelle is compassionate, warm, charming, and is generally welcoming to new friends. Despite her beauty and kick-ass combat skills, Isabelle is seen to be the moral compass that keeps her brothers Alec and Jace in check in tense situations, though she is also seen to have a bit of a defiant side. Isabelle is not afraid to speak her mind and isn't afraid to break rules, a trait she shares with her adoptive brother Jace. She is able to stand up to higher ranked individuals for what she believes in and fights and argues to get the point across whenever necessary.

She is a skilled seductress who can seduce any man, both Shadowhunter and Downworlder, into either complying with demands or maintaining confidential information. She enchants pretty much anyone who meets her. She is incredibly comfortable with her body; in the past, she wore revealing outfits with no qualms—a way of standing up to her mother's strict rules. During that time, she often acted as the bait or distraction to lure demons.

Isabelle is also equally skilled and deadly in battle, particularly when using her weapon of choice: her whip. Isabelle is feisty, talented, intelligent, and well-educated.

Isabelle is very supportive, protective, and loving towards her brothers, urging them to do what makes them happy. Isabelle often seeks to comfort those around her, although she also has a strict and disciplinarian side, particularly when it comes to training. She worries about her family a lot, and had a hard time accepting that Max was ready for his first real mission after training him for it.

She is fiercely loyal to her family and loved ones, willing to let go of her own happiness if it will make things better for them. Despite this, she will fight for what she believes is right even if the odds go against her, and would only cede and make the necessary sacrifice or adjustments when she sees the sense in it and how it would contribute to the greater good.

Skills and abilities

  • Nephilim physiology: Being Nephilim, Isabelle possesses a variety of enhanced physical and mental abilities granted to her by the angel blood of Raziel in her veins and also by the angelic Marks of the Gray Book. This includes enhanced strength, speed, agility, stamina, and coordination, which continue to improve over time and practice.
  • The Sight: As a Shadowhunter, Isabelle is able to easily see through most magical illusions and layers of glamour over reality.
  • Runic magic: Due to the angel blood in their veins, all Shadowhunters are all able to apply runes on their skin without any real danger. These Marks, in turn, give varied effects that serve to benefit the wearer.
  • Use of heavenly weapons: As a Nephilim, Isabelle is also able to perform tasks unique to their species, such as the ability to use and call on the power of angels for their seraph blades, as well as to handle any heavenly weapons or objects with effect, which would normally not work for other species. In particular, these are tools made of adamas and forged by Iron Sisters.

  • Expert hand-to-hand combatant: Isabelle is highly skilled in armed and unarmed combat.
  • Whip master: Isabelle is highly skilled in using a whip, able to use it to exert power and control over her enemies.
  • Forensic pathology: Isabelle is shown to be skilled in the study of forensic pathology and is referred to by Jace and Alec as the best in New York. She was even able to perform an autopsy on a strange new form of Forsaken and was able to successfully deduce what made it special. She is an expert, well-versed and highly-trained in studying the bodies of both mundanes and all creatures of the Shadow World.
  • Bilingual: Isabelle fluently speaks English and is shown to also speak Spanish.

  • Heavenly fire manipulation: After the heavenly fire-infused blade Glorious exploded, pieces of the shards plunged Isabelle in her back and pulled them out before healing the wounds. However her entire cellular system became infused with heavenly fire as it covered around her body which would kill her and any downworlder with demonic blood if she made physical contact. It was able to protect her against the atmosphere of Edom, and she learned to exert the energy of fire as a projectile beam and struck at Greater Demons which was lethal enough to kill them. Then when the realm was later destroyed by heavenly fire, a chain reaction occurred when Isabelle beamed it to kill Lilith causing the heavenly fire she had previously absorbed to be expelled from her whole body and into the sky over Edom.




When her mother Maryse was still the head of the Institute, they had a strained and tense relationship. Maryse often treated her coldly and sternly and was disapproving of her choices and lifestyle. Maryse eventually told her that this was because she reminded her of herself in her youth: stubborn and passionate, which she realized too late made her a danger, as she became passionate enough about her beliefs that she'd joined the Circle. When Maryse was dismissed as the head of the Institute, they were given an opportunity to finally have a mother-daughter relationship. Isabelle sympathized with her mother about Robert's affair and urged her to leave him.

Isabelle was once somewhat of a daddy's girl, having a close, happy relationship with her father. At one point, Isabelle found out that he had been cheating on Maryse. Isabelle kept it to herself, knowing it wasn't his secret to tell, but when Maryse found out, she immediately suggested that she should leave him.[36] Robert's visits to the Institute also became less frequent,[37] and when he did, it was on Clave business.[38]




Season One appearances: 13/13
The Mortal Cup:
The Descent Into Hell Isn't Easy:
Dead Man's Party:
Raising Hell:
Moo Shu to Go:
Of Men and Angels:
Major Arcana:
Bad Blood:
Rise Up:
This World Inverted:
Blood Calls To Blood:
Morning Star:
Season Two appearances: 20/20
This Guilty Blood:
A Door Into the Dark:
Parabatai Lost:
In main story and flashback
Day of Wrath:
Dust and Shadows:
Iron Sisters:
How Are Thou Fallen:
Love is a Devil:
Bound By Blood:
By the Light of Dawn:
Mea Maxima Culpa:
You Are Not Your Own:
Those of Demon Blood:
The Fair Folk:
A Problem of Memory:
Day of Atonement:
A Dark Reflection:
Awake, Arise, or...:
Hail and Farewell:
Beside Still Water:
Season Three appearances: 22/22
On Infernal Ground:
The Powers That Be:
What Lies Beneath:
Thy Soul Instructed:
Stronger Than Heaven:
A Window Into an...:
Salt in the Wound:
A Heart of Darkness:
Familia Ante Omnia:
Lost Souls:
Original Sin:
Beati Bellicosi:
A Kiss From a Rose:
To the Night Children:
Stay With Me:
Heavenly Fire:
The Beast Within:
Aku Cinta Kamu:
City of Glass:
All Good Things...:


See more here


  • Through Izzy's AA meetings, she found that one way to deal with her cravings for vampire blood was consuming sugar.[23]

  • She is portrayed by Emeraude Toubia; Romy Weltman portrayed a teenage Isabelle in the Season 2 episode Parabatai Lost and by Ana Marie Mallinos in A Heart of Darkness.
  • Her casting press release described her as an exotic-looking, model-beautiful Shadowhunter who, as an expert with her whip, is as lethal as she is attractive; is a trained fighter who can kick-ass in high-heels; and whose one weakness is her choice in men—always going for the bad boy.[39]


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