Arcadia Oaks-pedia
Arcadia Oaks-pedia
In the Old World, Gumm-Gumms stole our young and did something unnatural to change them. Their sole purpose: to spy on the world above.
Blinky to Jim and Toby about Changelings[src]

Changelings are Trolls that were altered by Morgana and the Gumm-Gumms so they can assume human forms. Changelings are sent to the human realm as spies, supplanting infant human babies who are known as the Changeling's Familiar.


The Changelings are trolls who were abducted by the Gumm-Gumms from their youth, who did "something horrible" to change them. They're swapped with their human counterparts at birth and have dwelt among humans for decades, therefore anyone could be a Changeling.

The Gumm-Gumms use Fetches to sequester human babies and replace them with Changelings. The Changelings adapt perfectly to the human world, being able to exist as any person. It is known that there are currently hundreds of Changelings around the world, as well as hundreds of baby Familiars in the Darklands. They are organized under a Changeling spy group known as the Janus Order.

In order for Changelings to maintain their human guises in the real world, no harm must come to their Familiars in the Darklands, hence why the Gumm-Gumms tolerate their presence in the Darklands. For some reason, their Familiars remain unaged, stretching back as far as 1894. It is possible that a Changeling's Familiar remains unaged because of the formula fed to them by goblins or because of the dark magic in the Darklands (or most likely both). If a baby Familiar was to be rescued from the Darklands, the changeling bonded to that familiar would lose the ability to transform into that human and would be stuck in their Troll form forever.

Despite possessing more advantages than a normal troll, the Changelings are seen as inferior beings by Gumm-Gumms and most Trolls, referring to them as "impures". This could most likely due to their two-faced natures and their unpredictability.

Similar to the Trollhunters, the Changelings have a code of three rules:

  1. There is honor among assassins
  2. Rule 1 is a lie; there's no such thing as honor
  3. Everything and everyone is a tool to get what you want

Physical Description[]

Changelings are shapeshifters, so they can either have a common appearance of a human and a troll.

Unlike other trolls, most Changelings (minus Gladys and Krax) demonstrate a more humanoid appearance and size in their troll forms.

In human forms, they speak like regular people. In their true form, their voices are usually more deeper and raspier.

Powers & Abilities[]

By connecting with a specific human, his or her Familiar, the Changelings are able to assume the appearance of that human when they wish. In their human forms, the Changelings also appear to be immune to the effect of sunlight just like Stalklings, regardless if they are in their troll forms as well, thus making them the perfect spies for the Gumm-Gumms. Some of them, like Stricklander and Nomura, are accomplished warriors.

However, they can be revealed if someone physically contacts them with a gaggletack (an iron horseshoe).

There are a few Changelings called Polymorphs that are able to assume the appearance of whoever they wish, human or troll, without the need of a Familiar. (Ex. Otto Scaarbach)


Although they're not affected by sunlight at all, a Changeling's most common weakness are Gaggletacks, which reveals a changeling's true nature through physical contact of anywhere on the body.

Changeling Races[]

Known Changelings[]


Appearances in the Trilogy



Part One[]

Part Two[]


Limited Series[]


  • In the episode "To Catch a Changeling" when Jim stabbed the Gladys changeling with Daylight, it revealed that, unlike trolls, who turn into stone when they die, changelings explode spreading dust everywhere. This is further proven by the blast that occurs when Janus is killed in Wizards.
  • Changelings are similar to the Zygons from the Doctor Who series. They can keep their human form as long as they have human captured and can switch between forms, much like changelings.
  • The concept is based on medieval folklore where fairies swap out human children with monsters. There are different versions of the story but in mythology, trolls are a type of fairy. It is probable that they have kidnapped the babies for years and the destination of the previous ones is not known, since in the original novel that it reveals on a big wave of children's mysterious disappearances.
  • At some point there's some resolution to the Darkland's Nursery story, but not really because there are a lot of babies that have been imprisoned there for a long time.
  • According to Aaron Waltke on Tumblr, Morgana originally created Changelings with her dark magicks — hence her nickname, "The Mother of Monsters". After her defeat, the Gumm-Gumms were forced to find a way to do it without her, in hopes of using them as spies to slip through the fetch and attempt to reopen Killahead Bridge. Over their centuries in exile, Gunmar and his forces eventually found a means of replicating the process (albeit in a ramshackle, inferior way) by harnessing the energy of the Darklands itself, and binding them to human spirits at infancy as a shortcut. Without the Darklands, there's no magic to sustain the changeling's familiar link to the babies — and the spell is broken.
  • According to Aaron Waltke on his Twitter page, due to their two-faced natures and tendencies of "bonding" with their enemies, they aren't exactly fully trusted too much on either sides of good or evil. Also because of their two-faced natures, the Amulet of Daylight would never chose a changeling to be a Trollhunter.
    • When Gatto once falsely accused Jim of being a changeling, this made absolutely no sense whatsoever, even since he touched a Gaggletack many times with his barehands (and in front of Blinky no less, so he had every right to be flabbergasted by this accusation).
  • According to Aaron Waltke on his Twitter, all changelings have unusual colored blood, which likely matches whatever stone they're made from.