Girl Genius
Girl Genius
This article is about a member of House Heterodyne. For others in the lineage or other uses, see Heterodyne (disambiguation).
This article is about a member of House Mongfish. For others in the lineage or other uses, see House Mongfish (disambiguation).
This article is about a member of the Clay Family. For others in the lineage or other uses, see Clay (disambiguation).

"I have a lot of things to do. If I drop everything to make
a girly fuss over him, we could all wind up dead." [1]

Agatha Heterodyne is the main character and eponymous Girl Genius.[2] She's a strong Spark and the last known member of the infamous Heterodyne family. Initially she was known by the name Agatha Clay. By the end of the First Journey she has taken possession of Castle Heterodyne and Mechanicsburg at large, earning her the indisputable title of Lady Heterodyne.

As the main character, a summary of every event in which the protagonist is involved would be impossibly long. This article is mostly limited to events that Agatha is aware of, that affect her deeply, and that are likely to come up again as the narrative unfolds. For a more in-depth analysis of her character, see Agatha's mad page.

Early Life[]

Agatha is the daughter of Lucrezia Mongfish and Bill Heterodyne. She was their second child, the first being Klaus Barry Heterodyne, who died while still very young. The circumstances of her birth are a mystery. The only clue we have is that, according to Lady Vrin, she is the holy child long sought by the Geisterdamen and later stolen by persons unknown . Wherever and however Agatha first appeared in the world, no one expected that there was a second Heterodyne heir.

Agatha was raised by her Uncle Barry until the age of seven. During her earliest years, he kept the family moving in order to stay hidden. [3] One day, Barry left on a secret mission, entrusting Agatha to the protective and tender Adam and Lilith Clay, and never returned. Adam and Lilith (in reality, the famous pair of constructs, Punch and Judy) raised her in Beetleburg under the name "Agatha Clay". Agatha remained unaware that she was either a Spark or a Heterodyne throughout her early life, thanks in part to a locket given to her by Barry. What became of her natural parents or her Uncle Barry is anyone's guess.

Lab Assistant[]

When the story opens, Agatha is 18 years old and headed for another day as student/assistant at Transylvania Polygnostic University, where she works under the watchful eye of Doctor Tarsus Beetle, who is the only other person besides the Clays who knows Agatha's true identity.

The day turns out to be exceptionally bad. She is startled by a foreboding electrical anomaly, her locket is stolen by Omar von Zinzer, Dr. Beetle is killed by Gilgamesh Wulfenbach, and she is expelled from the university. Later, she builds her first working clank in her sleep, which results in her being kidnapped and taken aboard Castle Wulfenbach.

On the castle, Agatha reluctantly pretends to be Moloch von Zinzer's girlfriend, until he threatens her. She also meets the students and gets to know Gilgamesh Wulfenbach, but cannot reconcile her enjoyment of his company with his having killed Dr. Beetle (self-defense or no), nor with his harsh treatment of the initially charming and heroic Othar Tryggvassen, Gentleman Adventurer. It's on Castle Wulfenbach that Agatha builds Dingbot Prime, acquires her first ally, Krosp I, and is introduced to the Jägergenerals.

It's also here where she has her first real adventure. The hive engine that was in Dr. Beetle's lab is activated by the sleeper revenant Mr. Rovainen in response to an accidental command from Agatha. With help from Agatha's Electric Foils and Dingbots, Gil and Agatha destroy the hive engine together. Euphoric, Agatha kisses Gil. He is instantly smitten and makes the worst marriage proposal Agatha has ever heard. Agatha takes umbrage at the idea of getting married just to annoy Klaus, but never gets a chance to answer Gil since Othar "rescues" her from Gil and is then thrown out a window , seemingly to his death. As Adam and Lilith attempt to whisk Agatha out of the Castle, Klaus recognizes them as the Heterodyne constructs Punch and Judy and deduces that Agatha is the child of Bill Heterodyne and Lucrezia Mongfish. Agatha escapes, but Von Pinn eliminates Punch and Judy.


Agatha and her liege cat , Krosp I, flee in a stolen airship with Othar who was waiting for her by it. They part ways when Agatha refuses to be Othar's 'plucky girl sidekick' and, with Krosp's help, pushes Othar out of the airship.

In the Wastelands, Agatha runs straight at danger to save Master Payne's Circus of Adventure from a rogue Spider Clank. The Circus then helps Agatha fake her death to throw off the Wulfenbach pursuit. Agatha acquires her second long-term ally[4] when Zeetha, Daughter of Chump, late of Skifander, takes Agatha as her Zumil. She acquires her third set of allies when the three wild Jägers that she freed from the town of Zumzum come to her aid at Passholdt. Agatha learns a lot about herself in the Wastelands, getting conflicting advice concerning heroics from Othar[5] and Master Payne.[6]

The Goddess with the Holy Child

While performing the role of Lucrezia Mongfish in the Circus's Heterodyne plays, Agatha forms an attachment to Lars. Following a command performance at Castle Sturmvoraus, the young actress is taken prisoner in rapid succession by Aaronev Wilhelm Sturmvoraus, then by Anevka Sturmvoraus, and then by Lady Vrin. Throughout it all, Agatha is alternately aided and hindered by the machinations of Prince Tarvek.

Vrin and the Geisterdamen use the "Holy Machine" to download another personality into Agatha—a personality that they believe is their goddess, Lucrezia Mongfish, Agatha's mother, and The Other. As Agatha fights a losing struggle for control of her own body, she builds a distress signal to warn the world and the Baron.

Agatha finally regains control when Lucrezia puts on the damping locket that Baron Wulfenbach repaired. When Lars intercepts a killing blow from the Baron meant for Agatha, Agatha learns about rage . She recovers her perspective only after becoming the subject of the first successful test of the calming pie. The Circus creates a mass illusion of the Heterodyne Boys to cover Agatha's escape from the Battle of Sturmhalten.


The Circus retreats to England, but Agatha advances to Mechanicsburg to take possession of Castle Heterodyne. There, she is elated to watch Gil stop an invading army of battle clanks. Agatha encounters competition from that other would-be Heterodyne heiress, Zola, but on the strength of some very fine coffee-making, she convinces former seneschal Carson von Mekkhan to get her into the castle.

Inside the castle, Agatha attempts to take control and begin repairs while Zola and the prisoners[7] hunt her.[8] Agatha is tested by the castle, and accepted as a Heterodyne. This gives her control of the castle and command of Mechanicsburg's air defenses, though her first command leads to a confrontation with Castle Wulfenbach.

As Volume 8 ends and Volume 9 begins, Agatha rescues Tarvek from one of her Castle's rogue defensive systems, drops him off in a "medical lab" after a brief peck to his cheek and goes in search of Gil (who is also trespassing in her Castle) so he can heal Tarvek. She captures Zola and brings Gil to the lab where Tarvek is on the slab. She heals a gunshot Gil suffered and apologizes for her anger at Gil for tossing Othar off of Castle Heterodyne. Tarvek is initially diagnosed with Chromatic Death , but is then proved instead to have Hogfarb's Resplendent Immolation. Using various torture devices lying around, Gil and Agatha construct a device to perform the Si Vales Valeo resurrection on Tarvek to clean out the disease. This involves hooking up Gil to Tarvek so that Tarvek has a healthy person to leach from and not die or go insane. The process fails due to the castle having an energy crisis, so Gil and Tarvek are fit with portable Si Vales Valeo devices so they can help repair the machinery that pulls energy from the Dyne, a river that emerges from the depths of the Castle and is infused with a powerful and mysterious energy. Just before descending into the basements, Agatha begins to show symptoms of Hogfarb's Immolation. When the Castle refuses to allow the deployment of her proposed solution to this problem, she shuts it down using the device that The Storm King conspiracy smuggled in and assembled. Following numerous further complications and interruptions, as well as Agatha and Tarvek dying (very brief and part of the plan), the process is successfully completed, healing all three of the victims. Agatha and her assembled friends and minions then proceed to restart and repair the Castle (along with Von Pinn/Otilia), fighting off repeated attacks from Zola and then Captain Vole and Professor Tiktoffen. Gil and Tarvek depart the scene for Castle Wulfenbach, voluntarily or otherwise. The Doom Bell is rung, and Agatha is officially announced as the Heterodyne and the new ruler of Mechanicsburg.

This of course doesn't make anything easier, as the Baron's reported death brings every crazed would-be Spark-ruler within 100 kilometers out of the woodwork to attack the town. On the positive side, the Jägers also return en masse and Franz the dragon awakens to defend the returned Heterodyne. Zeetha drags Agatha away from repairing clanks, and finds her a more suitable "suit" of armor to wear. Agatha is reunited with Tarvek, and they finally get to smooch . Unsurprisingly, it soon turns out the Baron is still alive, and proceeds to throw all of his assembled forces at Mechanicsburg as well. Things are further complicated by the arrival of The Real Knights of Jove, headed by Martellus von Blitzengaard (a/k/a Tweedle). Agatha fights off an attempt by an oddly-behaving Gil to carry her back to Castle Wulfenbach and is able to fully re-power Castle Heterodyne, which proceeds to drive the Wulfenbach armies from the town. Agatha then leads a procession to the Red Cathedral for further ceremonies establishing her as the Heterodyne. This process is simultaneously interrupted by the Baron's personal descent into Mechanicsburg with his Take-Five Bomb and Martellus's kidnapping Agatha and dragging her through the Monolith gate in the depths of the Cathedral.


Agatha, Tweedle, Krosp, and Violetta emerge into The Refuge of Storms, where they learn to their universal surprise that thanks to the Baron's Timeskip, they have lost two and a half years. Tweedle alters Agatha's body chemistry to make her physically dependent on his touch, but she is able in turn to transfer this need to a Wasp eater and successfully flee the Refuge. She is reunited with a fully-repaired Adam and Lilith, and learns things have not gone well in her absence; the Pax Transylvania is no more, the Other is loose on the land and The Long War has returned with a vengeance. An obsessed Gil controls the area around Mechanicsburg, and Agatha decides to travel to the intellectual capital Paris in hopes of finding a way to break the stasis-bubble around Mechanicsburg.

She and her companions set out on the Corbettite Railway engine the Wyrm of Limerick, but their journey is almost immediately interrupted when the train is attacked by Count Wolkerstorfer and the bear-like Swartzwalders, who are chasing fellow Wyrm-passenger Margarella Selnikov. The passengers are air-lifted to the Corbettite Depot Fortress of St. Szpac , where Lady Margarella goes rummaging through the fortress's vaults in fruitless search of (as it turns out) the semi-legendary Prende's Chronometric Lantern. In the process of this, she releases The Beast, which proceeds to rampage through the fortress. Matters are not improved by the arrival of Tweedle at the head of an army, still intending to claim Agatha as his bride. Agatha, Tweedle and the Monks band together in an attempt to contain the Beast.

Following a lengthy battle, Agatha and her allies manage to disengage the core mind of The Beast from the train's mangled body, at the cost of a single regular western monk. Feeling a sense of familial guilt in regards to the Beast's original creation, Agatha assists the monks in completing construction on a Sparky new super-train, a process which involves transferring the nearly-late Ulm's consciousness into the vehicle as its controlling intellect, with the Beast reduced to an impotent backseat driver.

At this point Gil arrives at the fortress at the head of his own army. The politics of the situation force him to be diplomatic, but his meeting Agatha in the flesh triggers the copy of Klaus installed in Gil's mind to step forward and take control. Fortunately, Spark that he is, Klaus-in-Gil allows himself to be distracted by the aforementioned mind-transfer. The procedure is a success, but a side effect is the temporary disabling of Agatha's locket. There follows a tense conversation between "Klaus" and "Lucrezia," which ends with their both passing out thanks to some drugged cake supplied by the Monks.

Agatha awakens on board the new train, en route to Paris. She learns that Krosp has taken his new army of Swartzwalders and decamped for parts unknown, but the Ulm-train's tunneling abilities allow easy bypass of Gil's encircling forces, and Agatha and her remaining followers (with the unwelcome addition of Tweedle) soon arrive in the City of Light.


Cleared to enter the city, Agatha learns that a Heterodyne branding craze has swept the commercial districts, and her name and image are plastered over every variety of product in a very unauthorized fashion. Unsurprisingly, she thus immediately attracts mostly-unwanted attention from all directions, the most prominent examples being university student/fledgling hero Jiminez Hoffmann and the remote-clank-body-operator Drusus Beausoleil. Beausoleil kidnaps her and drags her into a confrontation with would-be city-ruler Du Quay. The fallout from this latter fellow's thwarted take-over attempt leads to Beausoleil being revealed as a city secret-police agent, and Agatha meeting in person Simon Voltaire, the Master of Paris and his daughter Colette. As a Troublesome Heterodyne, Agatha is given three days residency inside the city limits by the Master to find what information she can on the time-bubble sealing Mechanicsburg, and thus goes in search of the relevant (and currently in-hiding) expert Dr. Dio Zardeliv and/or the aforementioned Lantern.

This quest leads her into Paris's figurative and literal underworld, where she dictates a treatise on Wasp-Eater creation for general publication, and has encounters with some of the independent fiefdoms who have carved out territory beneath the city: the Talpini mole-people, the revenant-infested Argurons with their princess Larana Chroma, and most importantly Hoffman's brother Aldin and the other inhabitants of the biblioholic Immortal Library. In this last location, she is helped to unlock the secrets of the notebook of the legendary super-Spark Van Rijn, and finds her way into his hidden Hermitorium, where she lets loose The Enigma (or The Muse of Time, or Lucrezia Mongfish, or whatever...) from the globe in which the now very-deceased Van Rijn imprisoned that mysterious entity two hundred years ago. Agatha and her entourage then descend into the sealed catacombs which still house the artifact-vaults of the area's former owners, the Corbettite Monks. The explorers briefly encounter Zardeliv and the Smoke Knight/Other-follower Madwa Korel. This confrontation leads to Korel absconding with an unconscious Zardeliv and (evidently) the Lantern, and the revelation that the vault they are fighting over contains the Lantern's Muse namesake, who was keeping watch over the original Storm King, Andronicus Valois. Valois, freed from the Lamp's temporal prison, is now a glowing Hulk-like berserker. He storms his way toward the surface, and Agatha and crew follow him, by a somewhat less direct route.

As all this is happening, an ongoing plot by the The Queen of the Dawn and her minions to take over Paris via Slaver-Wasp is nearing completion. And so, Agatha, Colette, the Queen, a swarm of Geisters, Valois and The Master himself all converge on the costume ball being theoretically thrown in Tweedle's honor by Xerxsephnia von Blitzengaard and her Grandmother. (Oh, and Tarvek's been dragged there too by the latter woman, though he and Agatha never actually get a chance to meet.) The resulting melee ends with the Queen (at least temporarily) thwarted, the Geisters, Valois and the Master all dead, the traitorous Beausoleil banished from the city, Tweedle literally claiming the Storm King's crown, and a newly Sparked-out Colette taking her father's place as the Master of Paris. In the face of the threat of the Other, Colette seals the city, and says that disruptive influences such as Agatha must leave. And so, Agatha and crew prepare to travel on to England, following a lead on Zardeliv, Madwa and the Lantern offered up by Ardsley Wooster.


On arrival in Londinium, Agatha is welcomed by spies Moonbark and Trelawney Thorpe. Agatha's party, with the addition of Miss Thorpe, proceed to the dock where the submarine transporting Korel, Zardeliv, and the Lantern is expected. The sub does arrive, at ramming speed. It transpires that the crew are all dead, victims of a poison gas. Dr. Zardeliv is among the corpses, as is a female passenger who is assumed (ahem) to be Korel. The Lantern is missing.

Thorpe, in a side conversation, informs Agatha that Tarvek is expected to arrive on a privateer, the Mopey Tortoise. Our gang learn at the dock that the Lantern was transferred to the airship Audacious, which should have been checked out by Her Majesty's Subhunter Serpent Ogo-Pogo, but the latter has been hijacked by an unnamed but politically important person who has been caught by the Mopey Tortoise. Wooster immediately concludes that the hijacker is Gil, whose arrival in England he considers about as destabilizing as the presence of a "loose" time-stopping device. Agatha is not allowed to meet with Gil when he indeed arrives, but does reunite with Krosp who comes with his army seeking refuge for his liberated creator Dr. Vapnoople.

Agatha is granted an audience with England's immortal and telepathic Queen Albia, who is very impressed with the contents of Agatha's brain, and officially grants permission for the latter woman to stay in England as long as she wants, and work on dispelling the Mechanicsburg time-bubble. Something that Albia doesn't tell Agatha is that she plans to lure the new arrival into becoming a permanent and technically-willing inhabitant in Albia's metaphorical Garden; Gil and Tarvek are explicitly not part of this arrangement. Agatha travels to her new quarters located in the undersea dome of the Queen's Society of Sparks, where among others she meets her new research assistant/Official Hunky Distraction Hadrian Rakethorn. She's able to get a little work done, finally, but all too quickly gets sucked into dealing with a murderous abomination-summoning conspiracy of many of the dome's inhabitants centered around an ancient temple hidden in the structure's basement. (Not to mention Tweedle turning up again, needing her touch to survive thanks to his own backfiring experiment.) This ends with most of said inhabitants dead or banished to parts unknown (including a mentally-revived Vapnoople), leaving Agatha and Co. with the chance to finally extract Lucrezia from her head and the Klaus-copy from Gil's. Following numerous setbacks, complications, incursions and delays, these tasks are finally achieved. However, in the process Wooster is killed and the dome's self-destruct mechanism gets triggered, the latter event forcing everyone to flee in submarines. They all get scooped up by a Great Cetacean, and Agatha has to don a hastily-constructed Sparky mermaid costume (again, as always, it's complicated..) and meet with the Cetacean's Deepdweller spokesguy. The meeting goes much better than it might have, the Cetacean tells Agatha of a Dyne-like contamination of some of their territory, and sends along a couple of the Deepdwellers as ambassadors to Albia. Everyone returns in triumph to a more public part of Londinium, where a large celebratory party is announced.

At the party, Agatha reunites with the Circus, who are giving a command performance. Truly free for the first time since she was six years old, Agatha decides to have a little fun: she dances with Gil, and she and the Circus throw together a large clank that gives current giantess Albia someone big enough to dance with as well. The big accompanying show also allows Zeetha and Axel Higgs the undercover "fake" Jaeger to enjoy a bit of public time together.

20210322 AgathaStaysInEngland

Agatha stays in England while her beaus are sent back to Europa.

Then back to work. Agatha puts the fear of Agatha into Bangladesh Dupree, she and her coterie manage to dimensionally stabilize visitor Kjarl Thotep, and then they find a lead on where to look for the Lantern and possibly deal with the Cetaceans' problems as well: a certain island in or near the vast British archipelago. Before then can set out, word arrives that the Polar Ice Lords have launched a massive attack on Europa, prompting Albia to banish.. dispatch Gil and Tarvek back to the Continent to deal with the problem. Tweedle stows away with them, while Agatha and her remaining followers (including Bang) set out to examine the island.

Arriving at Big Rat Island, the expedition is forced to abandon and self-destruct their airship after it is sabotaged by an agent of Lucrezia. They take up residence in the island's vast catacombs, constructed by a long-dead but powerful civilization, avoiding the local Lucrezia-clank copy, Korel, the English noblewoman Ariadne Steelgarter, who has some sort of history with Skifander, and the resident Spark Francisia Monahan. (Not to mention the last woman's giant Horrible Rats.) Agatha and Co. take possession of the Lantern, and manage to temporarily connect the local Queen's Mirror to the one located in Skifander. Agatha also learns more about the power-sources that allow Queens like Albia to arise, and helps get the local Flame burning/flowing properly; Lucrezia and Monahan inevitably fall out over who gets to tap into this, leading to the island being ripped apart as the two semi-Queens battle each other. The expedition escapes the carnage with the help of Albia, who is summoned via her daughter Neena's desperate plea for help. Agatha further learns (and helps hide) the fact that Albia's flame is at a low ebb; in return, Albia shares more information on the subject, fashions the Lantern into a new staff-like artifact that only Agatha can wield, and sends our protagonist back towards Mechanicsburg aboard a British fleet...

In Our Next Episode[]

As witnessed by Bangladesh DuPree, at some point in the not terribly distant future, Agatha (or someone who looks very much like her) will use a time-viewing device with Gil, Moloch and at least one Geisterdame in attendance.

Word of God stated several years ago in an interview[citation needed] that Agatha's future itinerary will include Africa, Skifander and the Geister homeland.

The in-comic side-stories "Ivo Sharktooth PJ", "A Mechanicsburg Solstice Story", and "The Mechanicsburg Guild of Monsters" are all set at some point after the Other War, and feature Agatha ruling (at a minimum) a freed Mechanicsburg as the official Heterodyne, though she only makes cameo appearances in these tales.

Command Voice[]

(See main article: Command voice.)

There is a series of incidents in which commands given by Agatha's voice (usually while in the madness place) exact obedience from servants of the Other.

However, a quality of her voice also clearly marks her as a Heterodyne heir.

Agatha's Spark[]


Agatha heterodyning

Agatha first performed the characteristic Heterodyne humming at age 5. This is the earliest breakthrough known, the second earliest being Gilgamesh Wulfenbach. Her uncle Barry feared that a breakthrough at such an early age could be disastrous, and built her a locket that suppressed her Spark until the story's beginning.

Like most strong sparks, Agatha's style is hard to define because she is marvelously proficient at a number of sparky disciplines. More importantly, she is still a student. However, she seems to specialize in mechanical engineering; her breakthrough creation is a clank, and she produces perhaps the smallest known clank soon afterward — Dingbot Prime — which assists her in building generations of miniature self-replicating clanks. These are a key factor in her first victory against Baron Wulfenbach. However, she shows a knack for surprisingly potent Death rays. Agatha has not yet created a construct in canon and her medical skills are limited , although she was able to replace Tweedle with a weasel.


(in order of appearance)

The Works[]

There are five cards for Agatha Heterodyne in the original version of The Works numbered Agatha Heterodyne 1 through 5. In each the epithets are Girl, Genius, and Spark.

Outside information[]

Agatha's appearance is based on the way Phil used to draw Kaja Foglio. Kaja explains in this old Livejournal post how Agatha was initially designed and why her hair is such a vibrant red-blonde color. (Although Kaja has appeared in the comic as well as herself.)

Agatha’s “heterodyning”—the humming/singing noise she makes while thinking Sparky thoughts—was partly inspired by Doc Savage’s famous trill (in the works of Lester Dent).[13] Doc would unconsciously produce the sound while thinking or fighting.

Before the publication of the Secret Blueprints in February, 2001, the March 2000 Dragon Magazine 269 contained a page of What's New with Phil and Dixie which had characters strongly resembling both Agatha and Krosp in one panel. (Krosp had previously been named in pages of that comic which appeared in Duelist.)[14]

In the print novels, Agatha is revealed to speak multiple languages, with Romanian being her probable native tongue.

Physical Prowess[]

In this picture, Agatha is holding onto the handle of a helicopter dingbot with her right hand while holding onto Doctor Tiktoffen with her left arm. Tiktoffen must weigh at least 100 kg (220 lbs). This is not an inconsiderable feat for a girl.


Impressive. Most impressive.

See also[]

External links[]

Secret Blueprints: Agatha Clay/Agatha Heterodyne


  1. Agatha settles Pinkie's hash.
  2. Master Payne's Circus of Adventure has already taken to referring to her in their shows as "Agatha Heterodyne, Girl Genius" when she catches up to them in England. Cf. Othar Tryggvassen, Gentleman Adventurer.
  3. Why Barry kept her hidden is not entirely clear, though Klaus seems to favor the theory that it was at least partly from him. "You've obviously been hiding from me all these years."
  4. The other members of the circus are also her allies, but they will soon part ways.
  5. "You ran straight at danger without even thinking.
  6. "Our lives ... are dangerous enough without questing for adventure."
  7. "Is everyone I know in here, or is it just everyone who hates me?"
  8. Zola promises freedom and gold to whoever kills Agatha, and more importantly, threatens to kill anyone who won't.
  9. "Fear not! Soon you will be safe !"
  10. "Build something."
  11. "That music!"
  12. "Showtime."
  13. Related to, or implied in part by, Kaja's comment here.
  14. Based on The Phil Foglio Gallimaufry.