Aldertree apparently used to be a field medic, before he eventually climbed up the ranks and became a diplomat.
At one point, Aldertree fell in love with a werewolf named Eva. After a year together, Aldertree went to Alicante for a summit, during which a Shax demon infiltrated Eva's home; people around her were massacred, but Eva was able to hide in the basement; but was driven mad by grief and shock. Unable to control herself, she Turned and attacked Victor when he arrived. Victor felt that he was left with no choice and killed her with his blade. Aldertree since came to see Downworlders and their nature differently and felt that Shadowhunters should never be with them.
Supposedly prompted by Maryse Lightwood, the Clave sent Aldertree as a replacement for then interim head of the Institute, Lydia Branwell, in light of Valentine Morgenstern's recent acts of war and the apparent defection of Jace Wayland, who was recently revealed to be Valentine's son. In an attempt to solve their problems, Aldertree initiated an investigation of all the Shadowhunters who had gone on missions with Jace and put the Institute on lockdown, much to Clary's dismay. At the end of it all, particularly after Clary's interrogation, Aldertree deduced that Jace was a traitor and launched a hunt and kill order for Jace.
Knowing that Jace's adoptive siblings had plans to meet with Jace, he struck a deal with Isabelle Lightwood that would guarantee his protection from the werewolves who'd been hunting him in exchange for surrendering Jace to the Clave. Isabelle agreed, and Jace was arrested after a brief reunion with the others.
Shortly after, Victor summoned the head of the local vampire clan Raphael Santiago for an investigation relating to the unrest among vampires in the city. Because of the absence of the alleged responsible party, the former head of the clan, Camille Belcourt, Aldertree decided to interrogate him further. Though Raphael truly did not know her whereabouts and was trying to find her, Aldertree was doubtful; he tricked Raphael and bound him to a chair, and began to torture him with a ray of concentrated UV rays—a new innovation from their research and development department. Because torturing Downworlders is against the Accords, Aldertree clarified that it was technically just motivation to get Raphael to give Camille up. He stopped only when Raphael's face had become heavily mutilated.
Aldertree interrogated Jace at the Silent City, during which he made Jace admit that he had feelings for Clary, his then believed sister, that he partly believed in Valentine's cause, and hat he cannot fully pledge his loyalty to the Clave. At the end of it, Aldertree decided to recommend to the Clave to sentence Jace to life. Before he could leave, Valentine infiltrated the City to steal the Soul-Sword and he was held at knife point as leverage against Jace. Jace decided to save Aldertree, allowing Valentine to escape with the Sword. Aldertree returned to the Institute with Jace, after which Jace was exonerated by the Clave.
After Isabelle was injured, Aldertree gave her a dose of yin fen, telling the desperate Isabelle that it would be the only way her infection would heal fast enough for him to clear her for the mission to the Adamant Citadel. Aldertree continued to give Isabelle yin fen and hung its availability over her head, secretly aware that she had become addicted to it, planning to control her through her addiction. Aldertree was impressed when Isabelle was seemingly able to quickly wean herself off of the drug and asked her out, but Isabelle declined.
Meanwhile, Aldertree remained distrustful of Jace, believing that Jace had intentionally let Valentine leave with the sword, despite the latter having saved his life in the process. For this, Aldertree benched Jace and put him on ichor duty. Jace confronted him shortly after and left the Institute.
When Alec found out about him giving Isabelle yin fen, he became furious—immensely protective of his sister—and used this information as leverage to regain control of the Institute. When Valentine infiltrated the Institute, Aldertree was able to hide away safely and worked with Alec to get past Valentine's men and to the rooftop in an attempt to shut off the Institute's angelic power core to hinder Valentine's plan to use it, as a substitute to lightning, to activate the Soul-Sword. They were unable to unlock the hatch to get to the power core because of the absence of a key—which was in his office and was at that time where Valentine was—and failed to override the mechanism to unlock it. When outnumbered by Valentine's men, Isabelle arrived and fought the adversaries all off before Alec and Aldertree could even join the fight.
After Valentine's attack on Downworlders at the Institute with the Soul-Sword, Aldertree was sent back to Idris to face reprimand.
|Season Two appearances: 8/20|
|This Guilty Blood:|
|A Door Into the Dark:|
|Day of Wrath:|
|Dust and Shadows:|
|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:|
- The character is a recurring role portrayed by Nick Sagar.
- He shares his name with two characters, both Inquisitors, from the books: Inquisitor Aldertree from City of Glass and Victor Whitelaw from The Infernal Devices.
- ↑ 1.0 1.1 1.2 2x05: Dust and Shadows
- ↑ 2x10: By the Light of Dawn
- ↑ 2x01: This Guilty Blood
- ↑ 2x03: Parabatai Lost
- ↑ 5.0 5.1 2x04: Day of Wrath
- ↑ 6.0 6.1 2x06: Iron Sisters
- ↑ Writer Pete Binswanger on S2E9 — Shadowhunters on Freeform
- ↑ 8.0 8.1 2x09: Bound By Blood
- ↑ 2x10: By the Light of Dawn
- ↑ 2x11: Mea Maxima Culpa