Alternate version
SPOILER WARNING: Plot details follow. Caution is advised!
I am Theresa Gray, daughter of a Greater Demon and Elizabeth Gray, who was born Adele Starkweather, one of your kind. I was the wife of William Herondale, who was the head of the London Institute, and I was the mother of James Herondale and Lucie Blackthorn. Will and I raised our Shadowhunter children to protect mundanes, to live by the Laws of Clave and Covenant, and to keep to the Accords. Once, I lived among the Shadowhunters. Once I might almost have seemed like a person to you.

–Tessa to Jocelyn in 1993, The Last Stand of the New York Institute

Theresa "Tessa" Gray is an American warlock, particularly a new kind of warlock—the rare half-Shadowhunter, half-Eidolon demon. She moved to London in 1878 and her life has since been entangled in the lives of the Nephilim.


Early life

Theresa Gray was born to an unmarked Shadowhunter named Elizabeth Gray and an Eidolon demon, disguised as the mundane Richard Gray—Elizabeth's husband and the man who would raise her as his own, and whom everyone believed was her father. Under normal circumstances, children of Shadowhunters and demons would be stillborn, but Elizabeth was able to give birth to Tessa not only because she bore no runes, but also because she wore the clockwork angel.[2]

For much of her early life, she was unaware of what she truly was and her true parentage. Conceived in London, Tessa's family moved to New York while Elizabeth was pregnant with her. After the death of her parents in a carriage accident when she was only three years old, she and her brother, Nate, were raised by her maternal aunt, Harriet Moore. She spent the majority of her life being overprotected by her Aunt Harriet and looking after Nate, who grew up spoiled. Tessa grew up taking comfort in books, dreaming of having the kind of adventures she read about. At sixteen, her Aunt Harriet died of what she thought was a fever. Upon her death, Nate arranged for Tessa to move to London with him.

Arrival in London

Tessa traveled from New York to London when Nate called for her, shortly after the death of their Aunt Harriet. Once there, a pair of mysterious and sinister women, whom she called the Dark Sisters, gave her a letter written in Nate's handwriting and told her that they've come to collect her on Nate's behalf.

The Dark Sisters soon revealed that they apparently had Nate as a prisoner, showing her their father's ring, one that Nate always wore, splattered with blood. They forced her to Change, or shape-shift, torturing her to learn quickly as well as threatening to harm Nate if she did not do as they asked. The Dark Sisters had made a deal with "the Magister" who had hoped to marry her and exploit her ability. In her isolation, she wrote letters to Nate about her loneliness and imprisonment.

One day, after Changing into Emma Bayliss, she was told about her marriage arrangement with the Magister, who had long been waiting for her. After a futile attempt of escape, she was finally rescued by the Shadowhunter Will Herondale. Tessa passed out in the midst of the fight against the Dark Sisters and was taken to the London Institute.

During her stay at the Institute, the head Charlotte Branwell promised to take care of her and help her search for Nate. There, Tessa befriended Jem Carstairs and the rest of the Institute's residents and staff, particularly Sophie Collins, the handmaid, while she had an uneasy relationship with Jessamine Lovelace, who wanted to move out of the Institute with Tessa.

When the investigation into her brother led them to Alexei de Quincey's house, she took the form of the vampire Camille Belcourt to infiltrate an exclusive party, with Will posing as her human subjugate and Magnus Bane, Camille's lover, as her guide. Once the human captive at the party was bitten, Will sent a signal to the Nephilim lying in wait to attack. Tessa then realized that the captive human was her brother, Nate.

During the battle, de Quincey went after Tessa, who was still in the form of Camille. Will, to save Tessa, fought him and ended up biting the vampire. After the battle, Nate was brought back to the Institute, where he was questioned and allowed to recover. Tessa got only a few moments with Nate since Jessamine, who wanted to marry a mundane so she can leave the Shadowhunter world, seemed insistent on caring for him instead, hoping Nate would fall in love with her.

Later, Tessa learned from Sophie that Will was being difficult about his treatment, which involved drinking buckets of holy water to bring up the vampire blood he had ingested, or else he would become a darkling. Tessa volunteered to take it to him in the attic, and Will finally obliged. During their rather intimate conversation, they shared their first kiss, before Will pushed her away and insisted that she leave him. After this evening, Will became even more standoffish and unfriendly towards her, much to Tessa's confusion.

To her surprise the following day, the Shadowhunters were discussing the further interrogation of Nate, possibly by the Silent Brothers. Annoyed, Tessa made it clear that their goals are not her responsibility, and that she did her part as they searched for Nate. Before leaving, she called them out for their pretentious attitude towards Downworlders and mundanes. After having some time to feel sorry about shouting at them, particularly since she was primarily only mad at Will, she left the Institute. She was promptly followed by Jem, who then began pointing out some places in London that might help her learn to love the city and even took her to his favorite—the Blackfriars Bridge. Here, Jem told her bits of his and Will's story and told her that he thinks she is no less human than him.

Unbeknownst to them, they were followed by a pair of automatons, one of them the being the clockwork coachman of the Dark Sisters, under the Magister's orders. Jem briefly engaged them before running off with Tessa and got as far as the Institute before Jem collapsed, his illness striking at a bad time; fortunately, Charlotte immediately came to their rescue. During Jem's recovery, he told her about his illness, his body's dependence on yin fen, so she wouldn't blame herself.[3]

Mortmain revealed

When Nate woke up, he quickly devised a plan that he secretly told the Magister of but continued to bear the semblance a frightened boy who wanted nothing more than to go home with Tessa and live a normal life. Selling her and the others lies and some half-truths about the true nature of his business in London, Nate falsely told them that de Quincey was the Magister and that the Dark Sisters would perform the binding ritual, a spell that would improve the automatons, that Magnus Bane had previously told them about on a full moon, the next of which was that very evening.

Nate's claim forced the Enclave to act immediately, leaving Tessa at the Institute with the non-Shadowhunters and the young ones, Jessamine, Will, and Tessa. The mundane previously interrogated by Charlotte named Axel Mortmain then arrived and fed them false information about de Quincey and the Dark Sisters, telling Jem and Will where they were, prompting the pair to respond and leave. With the Institute now vulnerable, Mortmain revealed himself as the true Magister and attacked the Institute with his automaton army, intent on taking Tessa. Nate's connection to the Magister was also revealed.

When confronted by Mortmain, Tessa recalled Will's words to her earlier, explaining that the British warrior-queen Boadicea was braver than any man because she killed herself rather than let herself be taken by the Romans. With this inspiration, she prepared to kill herself to escape Mortmain. However, she realized that if she Changed into the form of a dead woman, particularly Adams, whose form she had already taken while under the tutelage of the Dark Sisters, she would bleed convincingly. By Changing very quickly, and for a very short time, into a woman who had been shot, she convinced Mortmain that she was dead and he left when confronted by Will.

Will was momentarily affectionate, but then put an even greater distance between them. Later, she confronted Will, hoping to reconcile, but he was unkind, treating her like a prostitute and revealed that she was unable to have children as she was a warlock. Tessa left, hurt and confused.[3]

Over the next couple of weeks, Tessa grew closer to Jem, who volunteered to keep touring Tessa around London.

Tessa was present, and was a key witness, at the trial of Charlotte Branwell in front of the Clave, about the attack on the London Institute. Charlotte was given two weeks to find Mortmain or she would have had to resign as head of the Institute, and be replaced by Benedict Lightwood.

Tessa, accompanied Will and Jem, up to the York Institute to meet Aloysius Starkweather, who may hold a clue to the Magister's past. Jem gave her the Carstairs family ring, so that she could pretend to be a mundane girl, who was engaged to Jem.

Tessa was trained by Gabriel Lightwood to defend herself, in case there was an attack against the London Institute.

Sophie Collins came to Tessa with an invitation to a masked ball at the Lightwood's house, addressed to Jessamine from Nate. Jessamine slapped Sophie when she saw Sophie with it, so Sophie hit and knocked her out. Tessa sent Sophie to Will for help, and he placed a sleeping rune on Jessamine so that she would not wake up until morning, and tied her to her bed as a precaution. Tessa Changed into Jessamine, and Will accompanied her, so that she could sneak into Benedict Lightwood's house. Tessa met Nate, who danced with Jessamine, and reminded her that she was now 'Jessamine Gray'.

On the balcony at Benedict Lightwood's estate, Tessa and Will shared a rather intimate moment, which was interrupted by Magnus Bane. He was the one who helped them to get back outside of the house.

Later, Tessa once again Changed into Jessamine to meet Nate in a warehouse. However, that was a trap, as Nate had recognized his sister. Afterwards, Tessa was severely injured and Nate was fatally wounded.

Jem proposed to Tessa, and gave her his mother's jade pendant as a token of their engagement. However, Will arrived back from Magnus' house after the demon, Marbas, revealed that there was no curse on him. He talked to Tessa in private and declared his love for her, but she rejected him and told him that she was engaged to Jem.[4]

Imprisoned by Magister

Sometime after weeks of preparing for the wedding, Tessa finally realized that she was half-Shadowhunter, half-demon—an entirely new hybrid and immortal species that Mortmain wanted to progenerate with her.

She was kidnapped in an assault on the Institute at the delivery of Jessamine from the Silent City where she was taken to the Magister, who had taken up refuge in Cadair Idris near Will and Cecily's former home. Will then came and found them, but his long trip was to no avail as he was captured by his own stupidity and Mortmain's invisible wall. The rest of the Enclave then showed up, accompanied by three Silent Brothers: Enoch, Micah, and Zachariah.

In the fight with the Infernal Devices, it was revealed that her fiancé, Jem, had become a Silent Brother, Brother Zachariah. Since Silent Brothers cannot marry, they were separated.

Herondale family

Tessa married Will on March 9, 1879, and the two stayed together for almost 60 years. When around strangers, Tessa glamoured herself to appear older and look around the same age as Will.[5][6][7] During their thirtieth wedding anniversary,[2] Will took the bracelet Tessa wore on their wedding, which bore the wedding runes she could not, and had it redesigned with pearls.[8]

Tessa stayed with Will until his death in 1937. Afterwards, Tessa left London and stayed in Paris for ten years. She shared an apartment with Magnus for the first five, and he helped her cope with her losses.[2] During that time, they developed routines. She eventually moved out, realizing that Magnus' flamboyant lifestyle was not for her.[9]

While she hoped not to have to go through the pain of seeing her own children grow old and die,[2] she remained in contact and still visited them and her grandchildren often.[10] She also went back to using 'Gray' as her surname.[11]

Labyrinth refuge

Tessa began traveling at one point, staying particularly long at Los Angeles, where she kept an eye on her daughter's descendants, the Blackthorns, from afar.

Two years after the Uprising, Tessa was staying with Magnus in New York when Jocelyn Fairchild came to ask him to protect her daughter, Clary. Tessa, in the place of an Iron Sister, then performed the Shadowhunter children's ritual on Clary with Brother Zachariah. Pleased to meet her, Jocelyn took up the surname "Fray", a portmanteau of Fairchild and Gray, in honor of Tessa's friendship with her ancestors.[10]

Saddened by the Uprising, and the thought that the Herondales, the line of her and her husband, were gone, Tessa retreated to the Spiral Labyrinth and spent most of her time there, away from the rest of the world and its troubles. She instead focused on her research as a more scholarly warlock, aiding the Nephilim on occasion.

In September 2007, Tessa participated and fought in the Mortal War at Alicante.[12] Some time after the battle, she found out that Stephen Herondale's son, Jace, was in fact alive. She hoped to speak with him, though Magnus told her to give him some time to accept his own lineage before she burdens him with the past. While speaking with Magnus, Clary noticed her and even vaguely remembered her, thinking she was familiar, but did not remember from when. At that time, Tessa was wearing white, mourning certain deaths, such as Ragnor's.[13] Tessa returned to the Labyrinth afterwards.[14]

Full circle

In January 2008, during their annual meet-up at the Blackfriars Bridge, Jem surprised her by arriving as a mortal, no longer a Silent Brother nor dependent on his yin fen as he has been cured by Jace Herondale and his heavenly fire. Though surprised, Tessa welcomed him back into her life wholeheartedly, and the pair rekindled their relationship, sharing a kiss at the bridge. They agreed to see the world together, and Jem told her the "story of Lightwoods and Herondales and Fairchilds".

In May, they attended the wedding of Jocelyn and Luke. There, Jocelyn formally introduced her to Clary, who slightly recognized her. During the conversation, Tessa told Clary that she felt a kinship towards their families, and gave her her copy of the Shadowhunter's Codex, as well as the Herondale family ring that was once her son's, James, to pass onto Jace. While Jace has finally accepted the Herondale name, she, and Magnus, still opted to give him a bit more time to adjust and be happy on his own.

The following year, she and Jem got married in London, on the Blackfriars Bridge, attended by their new friends, as well as old ones—the ghosts of Jessamine and Will.[15]

Their search for the lost Herondale line descended from Tobias Herondale culminated in 2012 when Rosemary reached out to them. Following the lead,[16] the couple scouted the Shadow Market in August 2012.[17]

Her power to Change acted up during the trip. After she was fatally injured, Tessa found herself stuck in the Change, ultimately saving her from death, and Brother Enoch informed her that it was because she was pregnant.[16] Tessa waited until after they'd saved Kit Herondale and safely deposited him at the Los Angeles Institute with Emma and the Blackthorns before telling Jem.[17]

Tessa was momentarily affected by the illness affecting the warlocks caused by the blight. She and Jem search for a cure but her own condition delayed their search.[18] Eventually, Tessa recovered, proving to be the only warlock immune to the illness, and she devoted her time to finding a cure at the Spiral Labyrinth. When the cure was found by Emma and Julian, Tessa asked Emma to look after Kit and keep him away from battle. The precaution failed when, during the battle against the Cohort, Kit engaged the Riders of Mannan and unleashed his magic, though they managed to cover up the act as Ragnor Fell's.

Tessa visited Kit in the Silent City, where they kept him after the battle during the moments when they gauged the threat to his identity, then asked him to move with her and Jem to Devon and be part of their family. Tessa was surprised but pleased to hear Kit accept, and they left soon afterwards.[19]

A few months later in March 2013, at her manor house in Cirenworth, England, Tessa went into labor in the conservatory, with Jem playing on his cello to try and soothe her while she paced around the room.

During Tessa's labor, the ghost of Livia Blackthorn entered unbeknownst to anyone in the room, and started having thoughts about entering Tessa's unborn child to have a chance at a second life. Ty's voice, however, called her back to reality; in her shock and distress, she caused the walls of the conservatory to explode, alarming both Tessa and Jem, who thought it might be demons. Magnus Bane appeared and, noticing Livvy, assured them that all was well. After accepting some herbs from him Tessa allowed Jem to walk her back towards the house, where she later gave birth to her daughter, Mina Carstairs.[20]

With Mina's birth Tessa and Jem's family was complete, and they fell into a sort of routine, taking care of her and Kit while trying to make Kit feel loved and comfortable, and help him come to terms with his losses.[21]

Personality and traits

Tessa is an intelligent person. She is brave and strong-willed, and is incredibly caring. While she is generally warm, kind and understanding, Tessa can sometimes be very stubborn. She is also immensely curious and intensely determined when she decides to be.

Physical description

Tessa has smooth, thick, wavy brown hair, steely gray-blue eyes, an oval face, and a slender body. She is around 5'9—considerably taller than most girls and boys her age (before she stopped aging) at that time. While she used to think herself average, several of her friends have noted that Tessa is pretty and beautiful; not conventionally beautiful, but kindly attractive. Being immortal, Tessa stopped aging young and appears like a young woman in her early twenties.

According to Aloysius Starkweather, she strongly resembles her maternal grandmother—his daughter-in-law.

Skills and abilities

  • Immortality: Tessa is immortal, having maintained her youthful appearance since the 19th century.
  • Magic: After gaining the ability to perform basic warlock magic,[22] Tessa began practicing magic over the years and has even spent some time researching among warlocks at the Spiral Labyrinth.[23][14]

  • Changing: As a child of an Eidolon demon, she has inherited the ability to Change; the demonic power to shape-shift into another person. Unlike ordinary Eidolon demons like Mrs. Dark, Tessa can become whomever she transforms into as long as she has a physical object of theirs when she first turns into them. She achieves the Change by linking with a psychic impression or remnant of a person contained within an object. She can also Change by linking with a person's soul, as she did when she Changed into the Angel Ithuriel. In addition to their physical presence, Tessa is also able to touch the mind of a person and access their memories and thoughts when Changing, taking on their memories, mannerisms, and abilities.
    • After the events in Cadair Idris, Tessa's powers changed due to the heavenly fire. "There are some things she can no longer do, and some things she can do that she couldn't do before. She can no longer read the minds of people when she changes into them; however, she can do some basic warlock magic she couldn't before."[22][24]


  • Clockwork angel: the clockwork pendant designed to protect her. It was given to Tessa's mother by Mortmain. It contained the angel Ithuriel's soul and when he was freed, Tessa stopped wearing the necklace.[25]
  • Jade pendant: the whitish-green pendant Jem gave Tessa when he proposed to her. It was first given to his mother by his father. It has Chinese characters carved into it which translates to "When two people are at one in their inmost hearts, they shatter even the strength of iron or bronze," from the I Ching, the Book of Changes.
  • Pearl bracelet: the bracelet Tessa wore for her wedding with Will. The marriage runes were placed on the bracelet instead of her skin. On their thirtieth wedding anniversary, Will had it redesigned with pearls.



I could not have loved Will so much if I had not loved you as well. And I could not love you as I do if I had not loved Will as I did.

–Tessa about her love for Will and Jem, Clockwork Princess

Tarot Runes 2

Will was the first Shadowhunter that Tessa met. Will started out trying to keep his distance from Tessa, under the belief that he was cursed with endangering the lives of those he loved; when this was disproved, however, Will immediately confessed his true feelings for her. It had been too late, however, as she had just accepted Jem's proposal.

The pair consummated their relationship when they both thought that Jem was dead and that they were dying. When they survived the ordeal and returned to the Institute, Will courted her and eventually proposed to her. The couple wed on March 9th, 1879 and had two children. The couple remained together until Will's death, and Tessa loved no other—aside from Jem—even decades after his death.

Tarot Runes 10

Jem Carstairs is Tessa's current husband. Before he joined the Silent Brothers, they were engaged. When Jem was restored to his former, mortal self, he met with Tessa on the Blackfriars Bridge. When she found out that Jem had no intention of returning to his life as a Shadowhunter, and when Jem was unable and scared to tell her how he was feeling at the time, she asked him to be with her, to travel the world together. They immediately resumed their relationship and were married over a year after.


Charlotte Fairchild was the head of the London Institute when Tessa arrived. She was kind to let Tessa into the institute, and let her stay there, even though she was not a Shadowhunter. In Clockwork Angel, Charlotte had asked if Tessa wanted to stay at the institute, and Tessa said yes.


Sophie Collins was the maid at the London Institute when Tessa arrived there. She was very kind to Tessa and they became close friends and were able to trust each other.

Along with other warlocks Catarina Loss and Ragnor Fell, Tessa has become very close with Magnus Bane.


Tessa's parents died when she was quite young. Nonetheless, the few years they raised her were said to be full of love.

Tessa used to have a good relationship with Nate until he grew bitter and dissatisfied with his life. He became seemingly indifferent towards her, even willing to sacrifice her free will in exchange for his success—a revelation that shocked and hurt her. Despite this, Tessa loved her adoptive brother dearly and mourned his death, and even Nate seemed to express some remorse before then.

Harriet is Tessa's aunt, though not by blood—a fact neither knew during their time together. Harriet raised her lovingly, as she did her own child, after the Elizabeth's death.

Tessa eventually reconnected with some of her descendants after years of separating herself from them. She has since met Jace and Kit Herondale—the last of the Herondales directly descended from Will and their son, James—as well as the young Blackthorns of Los Angeles, descended from her daughter, Lucie.


Axel Mortmain (also known as the Magister), wanted to marry Tessa and had the Dark Sisters train her so she could be ready for him. Tessa then got rescued from the Dark House by Will Herondale and Mortmain was very mad at the Dark Sisters because he wanted (and needed in his opinion) Tessa for himself. He attacked the Shadowhunters and eventually in Clockwork Princess, captured Tessa for himself to marry and also to use as the final key in his plan.

He and his Clockwork army killed lots of Tessa's friends and close ones, and Tessa had always hated him from the moment the Dark Sisters had mentioned him in Clockwork Angel.



See more here


  • Tessa hates chocolates.[3]
  • Because of her Shadowhunter blood, Tessa is seemingly immune to the harmful effects of runes on other beings. Charlotte mentioned that they had attempted to use healing runes on her and the ink merely sank into her skin.[2]
  • Tessa always wore the pearl bracelet given to her by Will on their thirtieth-anniversary and the jade necklace given to her by Jem when he proposed to her.
  • As of the 21st century, Tessa apparently has around fifty living descendants.[26]
  • Tessa chooses to go by her "warlock name", a one syllable surname, Gray, as she does not want to be identified as a Shadowhunter, despite technically being a Starkweather by birth, and a Herondale and Carstairs by marriage.[26]
  • Jocelyn Fray formed their mundane surname "Fray", a portmanteau of Fairchild and Gray, as an homage to Tessa and her close relationship with the Fairchilds.[10]
  • Tessa, like Clary, is a main protagonist and narrator in Cassandra Clare's book series. In the first book, both are attacked and knocked unconscious by demons and are brought to the Institute by one of their potential love interests, particularly Will for Tessa and Jace for Clary. Both also walk in on their love interests playing a musical instrument in a room at the Institute; Jem was playing the violin, and Jace was playing the piano, and both mistook the girls to be their parabatai before seeing them.
  • Tessa's original surname was Fell, before the name was given to Ragnor Fell.[27]
  • Tessa's favorite ice cream flavor is Ginger.[28]


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