SPOILER WARNING: Plot details follow. Caution is advised!

We have eternity, so you'll grow to love me the way that I love you.

–Heidi to Simon Lewis, Familia Ante Omnia

Heidi McKenzie was a vampire. Once a mundane girl who frequented bleeder dens, Heidi was killed with vampire blood in her system and was Turned to be experimented on.


Early life

Heidi did not have a particularly good relationship with her family.[1] When she was 16, she went to a bleeder den for the first time,[2] looking for an escape. She was immediately addicted and became obsessed with the idea of becoming a vampire herself.[1]

TMI215 Heidimon06.png

Late in 2016, Heidi went to one where she was a frequent customer. She spotted the vampire Quinn entering with a first-timer Simon Lewis and approached them. Quinn introduced them, and Heidi bit her lip, making it bleed to entice Simon. Though initially hesitant, Simon gave in, and the intoxicated pair stayed together and went outside, where she continued to let Simon feed on her.

After her time with Simon, Heidi crossed paths with Quinn. He fed on her, through her ankle, and was unable to control his hunger until he, apparently accidentally, drained her of blood and killed her. Simon's fingerprints were taken from her bracelet and he became the primary suspect for the mundane police investigation into her murder. Simon returned to the bleeder den in hopes of remembering if he did kill Heidi and turned himself in to Ollie (Detective Olivia Wilson) who'd arrived at the scene, but Simon realized that she was killed by Daniel and killed him when he refused to take responsibility. Brooklyn vampire clan leader Raphael Santiago then encanto'd Ollie so she would close the case, telling her that her real murderer had disappeared and making her forget Simon.[3]

Turned for testing

Raphael, however, did not leave Heidi to simply die. Heidi ended up with vampire blood in her system, so when she died, she became a fledgling. Raphael rescued her from the morgue and helped her through her transition and had since kept her in the basement of the Hotel Dumort. Heidi took her Turning well, excited about the prospect of being a vampire, and often pestered Raphael about wanting to see her sire, Simon, while Raphael continued to insist that she still had some adjusting to do.[2] Heidi clung to her first impression of Simon when they met at the bleeder den, hopeful that he cared about her.[4]

Raphael burning Heidi.

Meanwhile, she was also subjected to Raphael's experiments, in hopes of figuring out how to be a Daylighter like Simon.[1][4] He burned her with UV light, keeping her sedated with dagget root—a vampire tranquilizer.[5] Heidi grew more restless over time, desperate to see her sire again. Once, she threatened Raphael; Raphael made her believe that he was letting her go before drugging her again. When Raphael stepped out of the hotel, Heidi took the opportunity and escaped.[2]

After getting out, Heidi felt her thirst for blood and went to a blood donation unit truck to get some. She first stole bags of blood but decided to feed on the mundane worker onboard the truck instead. She'd drained him of his blood and killed him but, apparently upon remembering Raphael, she decided to Turn him.

Obsession with Simon

Heidi in Simon's bed.

She then headed to Simon's boathouse, hoping to see Simon, but was met by Raphael instead. Heidi was able to fight him off and knocked him out with dagget root. As revenge for her suffering from his experiments, she chained Raphael down on a rooftop to be burned by the sun as soon as it rose. Meanwhile, the man she'd Turned and buried in the building's basement was killed by the Shadowhunters who also later released Raphael.[1]

"You don't deserve him."

Heidi did not stop trying to pursue Simon. Using Raphael's phone, she led him to her new hiding place. Though Simon became sympathetic to her and offered to be there for her when she needed him, he pulled away when Heidi tried to kiss him and explained that he had a girlfriend. Heidi pretended to understand but followed him to find out who the girl was. She found him at the Hunter's Moon and saw Isabelle Lightwood giving him a kiss and mistook her for his girlfriend. She confronted Isabelle outside the bathroom but stood no match against the Shadowhunter, though Simon came in time to stop Isabelle from killing her or taking her in for attacking her.

Simon accompanied her back to her hiding place, and she was under the impression that he was on her side, only to be ambushed by members of the Praetor Lupus who sedated and cuffed her to keep her under control. The Praetor was meant to help her,[4] and they'd kept her locked in the Praetor House in Long Island for a time,[6] but her Praetors were killed by Jace a couple of days after. Jace stuffed her into a duffel bag and took her to Lilith.

"Time for a good old family dinner."

Simon: "So what's your game plan? You're gonna make me feed on my family, and then what?"
Heidi: "And then we'll be free to start a new life together."
―Heidi and Simon, Familia Ante Omnia

Lilith manipulated Heidi into going after Simon's family, convincing her that letting his family know that he was a vampire, and them rejecting him, would force them together. Lilith also warned Heidi not to attack Simon as it would trigger his Mark. Heidi tied up his family and cut into Rebecca's skin to make her bleed. Simon provoked her by bringing up her past, but Heidi remembered Lilith's warning and laughed it off. To finally get what she hoped to accomplish, she released Rebecca and let her go to Simon, and when the hungry Simon finally fed on his sister, Heidi left.[7]

Jordan Kyle initiated a hunt for Heidi with the Praetor and a group dedicated to capturing her was formed. They'd tracked her down to the sewers one evening where she had just finished feeding off of a mundane. Heidi killed a Praetor named Nick, renewing Jordan's determination to hunt her down. Heidi went to the Hotel Dumort, now under the leadership of Griffin, for protection but was turned away for her past actions.

Heidi decided to turn the vampires and werewolves against each other, starting by using encanto on a girl named Nora and leaving her as a lead for the Praetor to follow; the woman told them that Heidi was being protected by the Brooklyn vampire clan, prompting Jordan and the Praetor to barge into the Hotel in search of her. Heidi returned afterwards and convinced them to attack the werewolves at the Jade Wolf as revenge.[6]

Everyone in this room should be proud... proud to call yourself a vampire. If that makes people afraid, then let them be afraid. We should never, ever be ashamed of who we are. The days of being locked out are over. If they don't let us in then we break down the door. Anyone who stands in our way will face the consequences. The Downworld is ours for the taking. Shadowhunters have had their day in the sun, but our night... has come. It's our time to rule. To the Night Children!

–Heidi rallying vampires of the Brooklyn clan, To the Night Children

Heidi left the dirty work to the other vampires so she could claim innocence after the incident. After celebrating with the vampires, Heidi, upon finding out that Maia and Jordan survived the attack and were thus witnesses against her, went to the New York Institute and turned Griffin, Joshua, Elle and some others in for the attack on the werewolves in exchange for absolution for her past crimes. She returned to the Hotel and declared that they must have a traitor in their midst, once again claiming innocence.

Heidi shriveling as she dies from ingestion of holy water.

She also went to Nora, being someone who could testify to the Shadowhunters against her, and hypnotized her to stop breathing. The girl was saved by the doctors and later by Magnus Bane, however, and was able to give Alec the evidence he needed to bring her in. Maia, however, had taken matters into her own hands and confronted Heidi. In the fight that broke out, Heidi bit Maia, unaware that the latter had holy water in her veins, killing her almost instantly.[8]


Season Two (2B) appearances: 1/20
Mea Maxima Culpa:
You Are Not Your Own:
Those of Demon Blood:
The Fair Folk:
A Problem of Memory:
Day of Atonement:
Alluded to only
A Dark Reflection:
Awake, Arise, or...:
Hail and Farewell:
Beside Still Water:
Season Three appearances: 7/22
On Infernal Ground:
Appears; eclipsed
The Powers That Be:
What Lies Beneath:
Thy Soul Instructed:
Stronger Than Heaven:
A Window Into an...:
Salt in the Wound:
Mentioned only
A Heart of Darkness:
Familia Ante Omnia:
Mentioned only
Lost Souls:
Mentioned only
Original Sin:
Beati Bellicosi:
A Kiss From a Rose:
Mentioned only
To the Night Children:
Stay With Me:
Mentioned only
Heavenly Fire:
The Beast Within:
Aku Cinta Kamu:
Mentioned only
City of Glass:
All Good Things...:


  • Heidi is an original character created for the show, but her role is slightly similar to one that Maureen Brown had in the books.[9][10]


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