|Name|| Castle Heterodyne, der Kestle|
|Age|| Several centuries|
|Occupation|| Home of the Heterodyne family, giant mechanical deathtrap, |
|First Appearance|| |
|Parents||Knife (original builder), Faustus Heterodyne (who gave it a mind)|
Castle Heterodyne (or as the Jägers say, der Kestle) is the ancestral home of the Heterodyne family, and a character in its own right. It is built at the source of the River Dyne, from which it extracts the energy to power itself.
Castle Heterodyne was originally built in 1042 by Knife,  who seems therefore to be the first Heterodyne to drink the water of the Dyne.  This first fortress was accidentally destroyed by Egregious Heterodyne.  Evidently, the Castle was rebuilt and destroyed two more times “before the present structure was erected in 1298.” 
The Castle was first programmed with self-awareness by Faustus Heterodyne (perhaps in 1677), one of Agatha's mad scientist ancestors. Since then, it has been considered to be alive. Its charming personality — it thinks it has a sense of humor — is said to be a copy of his.
Main Article: Attack on Castle Heterodyne
The Castle was nearly destroyed 19 years prior to the beginning of Girl Genius in a mysterious and as-yet-unexplained attack by The Other. Many people were killed that night, including Agatha's infant brother Klaus Barry Heterodyne and the then-new seneschal (the son of Carson von Mekkhan). It was the same night that Lucrezia Mongfish went missing.
Subsequent History Edit
After Baron Klaus Wulfenbach returned (from wherever Lucrezia had sent him prior to her marrying Bill Heterodyne) and, eventually, took over Mechanicsburg, the Castle released an assistant from the TPU team to procure food, tools, and more help. The Baron, ever able to apply the right monster to the job, negotiated with the Castle and proceeded to send it his most difficult prisoners. This is considered the ultimate punishment detail, as the chances making it out alive again are extremely slim.
Such is the situation when Girl Genius opens.
Story Start Edit
Some of the current inmates in Castle Heterodyne play significant roles in Agatha's story.
It is currently unknown how far the Castles' systems extend into the surrounding city of Mechanicsburg, having control of Mechanicsburgs' air defenses know as the Torchmen. When the Castle was shut down, large sections of the city systems — clocks, fountains, draw bridges, lights — immediately stopped working.
Intelligence and behavior Edit
Castle Heterodyne is, in effect, a giant clank. One of its primary interfaces is located in the Heterodyne family crypt, and has the limitation at that location of being unable to speak directly, but only through a human linked to it.
On two occasions so far, the scene cuts away to show us three lights during interactions with Agatha Heterodyne. It appears to be strongly suggested that each light comes on in turn when an important stage in confirming Agatha to be the new Heterodyne is reached, as the first time this happened was when Agatha's voice was found to be similar to that of Lucrezia Mongfish, and the second time was after a blood sample from Agatha was analyzed, confirming her to be of Heterodyne descent.
Recovery and Post Recovery Edit
After many years of slaving away and dying at their wrenches by Wulfenbach prisoners, led by Hristo Tiktoffen now deceased, and days to weeks of adventurous repair work by Agatha Heterodyne, her two suitors, Gilgamesh Wulfenbach and Tarvek Sturmvoraus, along with her minions, led mostly by Moloch von Zinzer, Castle Heterodyne is now fully functional. It has loosed its hordes of parasites, monsters, clanks and who knows what else upon the Wulfenbach forces that are bent on destroying it.
Named locations within Castle Heterodyne Edit
- - there is an implication this may be the same as the Prisoner's Gate
- Prisoner's Gate
- Gate of Chimes
- (in the Tower of Prisms)
- Chapel of Bones
- (presumably the Seraglio of Satyricus Heterodyne)
- Heterodyne family crypt
- Red Playroom ( )
- (In times when the ruling Heterodyne is of a more monogamous persuasion it is evidently used as servant's quarters)
- Venthraxus Heterodyne's personal kitchen
- Vipsania Heterodyne's
- The Great Movement Chamber, from which The Dyne springs (mentioned first ).
- Throne of Faustus Heterodyne
- (containing the Blue Corridor)
- Tower of Green Bone.
Monsters, Clanks, and Traps Edit
- Fun-Sized Mobile Agony and Death Dispensers
- The Happy Fun Ball of Death
- Nyar Spider
- Venomous Rafter Toad
- Amusing Octo Electrocuter
- Artful Blood Drainer
- Human to Pet Brain Transplant Device
- Iago's Mechanicsburg Toaster
- Many-Brushed Birdbaths
- Scream Emulator
Rules of Castle HeterodyneEdit
As thoughtfully compiled by untold numbers of prisoners at great hazard, and explained by surviving sources:
- Flagstones and parts of the ceiling marked in white are traps that will kill you. (Source: Zola "Heterodyne" when .)
- Duck under any doorway taller than one meter; these will also kill you. (Zola)
- Don't touch any metal surface; it will also kill you. (Zola)
- Gold coins are metal too: Don't try to pick them up; they are pit traps. ( .)
- Refusing to repair the Castle will get you Ardsley Wooster) . (
In our last episode... Edit
Following Judy's instructions , Agatha travels to Mechanicsburg, speaks to the broken Castle , and the Castle. Zola "Heterodyne" also the Castle in a quest for legitimacy, though she plans to kill the Castle rather than repair it.
It gets to be quite crowded inside the walls of Der Kestle. Tarvek the Castle and joins Agatha's party. Gilgamesh Wulfenbach, Schmott Guy with Zeetha. Von Pinn . Various parts of the Castle are still bent on killing everyone; . See also forum discussion on Multiple AIs in the castle. Outside, Klaus some of his special service units to destroy the Castle.