Gustav is always shown wearing a shiny monocle over his left eye. He is typically depicted wearing a long black overcoat over a white shirt and black trousers. He wears a black bow tie and brown scarf, the latter of which he either tucks into his coat or drapes smoothly over his shoulders.
His clothes are both elegant and obviously expensive (as is his umbrella, which he carries with him constantly), and overall make him seem rather like a "wealthy entrepreneur."
He has sharp, hawkish eyes, and some of his brown hair is grey. It is difficult if not impossible to determine his exact age; on first glance, Gustav looks "rather young" but has also been described as "middle-aged," owing in part to the grey hairs.
Narita has also described his eyes as "looking nothing less than evil."
Gustav is a well-spoken individual: his speech is exceedingly fluid and polite in such a way that people don't dare to interrupt him (even when he rambles). His 'ramblings' tend to be a series of rhetorical suppositions (such as his musings on rainbows) leaning toward both the philosophical and practical.
One of Gustav's notable quirks is the points 'system' he has with Carol, awarding her a number of points for her answers to his rhetorical questions. It is unknown if he actually has some sort of system in mind when judging her answers, though it is likely the points are arbitrary. His emphasis on etiquette by modern standards is somewhat old-fashioned (as evidenced when he tells Carol that it is rude for ladies to point at people/objects). He is always extra-courteous to clients.
He is an experienced journalist and prefers investigating on-scene rather than from the comfort of his desk. He and Carol often travel as a result. Furthermore, he is competent in a fight, easily able to fend off Graham Specter's men when they hijack their westbound transcontinental train in 1934.
It is clear that he is protective of or otherwise cares about Carol to some extent, as seen when he carefully guards her from Renee Parmedes Branvillier in 1934.
In December, Gustav and Carol board a westbound transcontinental train for Chicago, Illinois. Gustav intends to visit the Daily Days staff in other cities and to photograph them, and has opted to bring Carol along to further their training.
In their plainly furnished First Class compartment, Gustav reads a newspaper while Carol watches the passing scenery through the window. Carol excitedly exclaims when she sees a rainbow in the sky, and Gustav muses that a rainbow is indeed a wondrous occurrence that soothes its onlookers. He wonders why a phenomenon reminiscent of a child's thoughtless drawings draws the admiration that it does, and points out that one could and that some do view a rainbow to be a harbinger of disaster.
He asks Carol if she has thought about such things, but she says she has not; in her opinion, a reporter's job is not to 'think about things' but to "report to others the outcome of what's already happened."
Gustav says her answer is "only" worth about three hundred and nineteen points, and urges her to always consider the authenticity of information, even after taking possession of it. Neither she nor he can allow themselves to be satisfied with "the mere knowledge of the veracity of the facts," for that is their responsibility as journalists.
Puzzled, Carol asks him what there is to think about; after all, she cannot change the facts just by thinking about them. Gustav argues the opposite: depending on how one thinks, the facts of both the past and future are both capable of changing. Furthermore, information only gains value after one think it over with one's mind and heart.
Their conversation is interrupted by a muffled racket in the corridor. Several knife-wielding men wearing bandannas over their mouths enter the cabin, one of whom shouts for Gustav and Carol to remain quiet. Instead, Gustav swings his folded newspaper down onto the table, the sound of which is all but ear-splitting. At the same time, he uses the hooked handle of his umbrella to trip a new arrival.
As the man falls backward, Gustav throws the newspaper at one of the two men in the hallway and strikes him with an "unusual uppercut" that sends him flying into the air. He then snatches the third man's gun and neutralizes him with a swift, punishing kick between his legs. The entire encounter lasts no more than a few seconds.
Carol asks Gustav is all right while he stows the gun, and Gustav smiles and apologizes for using the newspaper before giving her a chance to read it. He then uses the attack as a didactic example of his earlier point: in interpreting preexisting information, he had foreseen the possibility of an attack. In other words, it was through thinking about information that he was able to defend himself and evade danger.
The revelation that Gustav knew all along about the possibility of an attack shocks Carol who wants to know they boarded the train at all Gustav admits that he only arrived at such a conclusion after it was too late to return the tickets, having given the President their receipt ahead of time.
Their conversation is interrupted yet again when they hear someone outside the cabin door ask Gustav "...You...who the hell are you?" in a voice filled with malice. Gustav introduces himself in both name and occupation, including that he 'dabbles' in information.
Still hostile, the man says and his gang had intended to herald their Chicago arrival via a train robbery, and then demands to know how Gustav anticipated their attack. Gustav reminds him of the nature of his profession, and that the event's conclusion will not change per the man's whims. There is no changing the past, no matter "how much you search for meaning in a completed action."
With Carol present, the man is increasingly disinclined to go through with robbing them; however, he still wants to know how Gustav acquired his information. After a spot of negotiation, Gustav agrees to the man's terms and prepares to share the "details surrounding a certain incident."
He thus advises Carol to pay attention, as it would behoove her to know the story surrounding a man named Claire Stanfield and the people associated with him - though this particular tale is centered around a woman who is practically his other half. After inviting the man in for tea and pouring him a cup, Gustav proceeds to relay the events of 1931 Another Junk Railroad.
Gustav wraps up his account with a rundown of what happened to Graham Specter's gang in the two years since those events: how they (unlike Jacuzzi's Gang) made too much commotion in territory controlled by larger mafia families; how they had become targets; and how the Russo Family made them a certain offer. He also remarks that the train Graham's gang boarded has a security problem: once the train passes a certain point, it is impossible to know that a robbery has taken place in First Class until the train reaches the station.
Gustav remarks that Graham's gang could potentially boost their own morale by emulating their idol Ladd Russo, who had once hijacked a train in 1931). Further still, he has heard a rumor that one of the First Class passengers is an unpopular miser. Although Gustav had thought it was unlikely they would take action, he had been in the midst of preparing his newspaper gun when he had heard them coming down the corridor.
The other man in the room - none other than Graham Specter - cackles upon realizing that he was just a tool through which Gustav could relate his long tale to Carol. While it is not the first time Graham has heard of "Immortals" and "Huey Laforet," he finds his tea delicious and decides to let Gustav off the hook.
As Graham prepares to leave, Gustav offers him one more piece of free information, as thanks for the compliment: that there happens to be a man in the adjacent cabin who always carries around large amounts of cash and jewelry for the sake of being ostentatious. His suggestion that this man might be the "miser" that Graham has heard of causes Graham to frown, but he smiles after a moment before slamming open the door and shouting for his men to get off the floor.
The first to stand (Shaft) complains about Graham's persistence to no avail, and then asks if Gustav would pour him a cup of tea as well. Graham instructs him to hurry, and exits with the other two delinquents in tow. Once alone, Shaft pours himself a cup of tea, bows, and apologizes to Gustav for the trouble. Gustav surmises that Shaft must be one of Sham's vessels and admits that he is a tad surprised, as he had not expected to see Sham mingling with the likes of those delinquents. Sham quietly requests that their meeting be kept secret, insisting that "Master Huey" has no need to be aware of it.
Gustav is intrigued by what seems to be Sham acting independently of Huey's will, and - given that Sham sells the Daily Days information on the side - wonders if Sham is planning on overthrowing Huey and Nebula. Sham claims he wishes only to have freedom, remarking that Huey is not the only human he has a personal interest in - Graham is such a human, too.
Hearing Graham's voice in the hallway, Sham gulps down the rest of his tea and once again requests Gustav's silence regarding their information exchange. With that, he opens the door and joins the others in flight. In the ensuing tangible silence, Gustav invites Carol to ask him any question she may have.
At Carol's disapproval over his encouragement of robbery, Gustav explains that the miser is one Mr. Turner who once managed to worm his way out of paying full price for Gustav's information on the grounds that he "could not trust" it - before using that information to make a great deal of profit. As illegal as it might be, Gustav feels that the robber is justified - and that the robbery serves Turner right. Even so, Carol feels that it is still an abuse of power.
When the rainbow disappears and Chicago's high-rises appear on the horizon, Carol asks Gustav what he thinks will happen in the city. Gustav points out that not even their organization can gather information on future events, and as such, thinking and theorizing is all they can do in the meantime.
Upon arriving in Chicago, Gustav and Carol stay the night at the Gansluck Hotel. They have a breakfast of ham and eggs the next morning, where they are waited upon by another Sham vessel.
Ten days later, the two head downtown to visit Nebula's headquarters. Carol is so enamored with the exterior that she wants to photograph it, but Gustav vetoes this desire on the grounds that the DD agency already has a recent photo of it. However, he subsequently advises her to consider a wide variety of opinions - rather than just his - before deciding on her own.
On their way in, Carol squeals when Senator Manfred Beriam pass them by. Gustav instructs her to remain calm, as the Daily Days treats all valuable contacts - regardless of those contacts' personal statuses - as equals. They proceed to take the elevator up to Nebula's rooftop garden, where Carol meets with Nebula Chairman Karl Muybridge and is all nerves. Meanwhile, Gustav consults with his contact.
After thirty minutes, the two take the elevator back down to the first floor grand hall. Gustav leads Carol over to a bench, lecturing her on her deportment all the while, before departing to buy a drink. He finds Carol talking with Renee Parmedes Branvillier, who claims that she is certainly not thinking of kidnapping Carol for an experiment when Gustav confronts her.
Gustav cooly comments that Renee does not normally lounge about the building entrance, which Renee acknowledges; she replies that she wanted to pay the visiting Daily Days personnel a visit. Putting a protective hand on Carol's head, Gustav inquires into Renee's recent activities--including whether or not Nebula's 1200 Mist Wall employees' incomplete immortality was a success or failure.
Renee does not yet know as her experiments require further observation, and she complains that quite a few people have been causing trouble for Nebula as of late - such as Homer and his men in New York, and the Russos in Chicago. Gustav's pointed warning that she is veering into top secret information causes her to clap her hands over her mouth, and she agrees that she was careless. Had she continued talking, she would have had to "finish [Carol] off to keep [her] quiet." Carol laughs, thinking it a joke.
The three of them continue to chat a little while longer before parting ways. As Gustav and Carol leave the building, Gustav asks Caro what Renee 'did' to her, much to Carol's confusion. He warns her that she must be careful around Renee and to never find herself alone with Renee again, refusing to elaborate until they are clear of the premises: "When she said she would finish you off...she meant it."
Carol laughs as they reach and start crossing a bridge spanning the Chicago River, having never before heard Gustav 'make a joke'. Gustav retorts that he was not joking, but supposes that he does not have the right to impose he will upon her should she choose not to believe him. However, as her superior, he cannot watch her walk blindly into danger.
Not a second later, Carol walks right into the larger of two individuals on the bridge. She immediately apologizes, but is swiftly scared into silence by the individual's - Frank's - giant size. When she sees the second individual, Rail, she screams at the sight of Rail's multiple prominent scars. Gustav chastises her for her rudeness, and Carol apologizes again once she calms down.
Repentant, Carol suggests that she and Gustav treat Rail and Frank to lunch as a conciliatory gesture. This means that Gustav will be paying for lunch, and he leaves to find a nearby vendor. Upon his return to the Wrigley Building, laden with a huge quantity of hot dogs, he informs Carol that the cost of lunch will be deducted from her salary.
Gustav and Carol converse with Rail and Frank until a passing-by Graham overhears Rail admiringly mention a "bomber chick" who is a 'wizard' with explosives. Correctly guessing that the bomber chick is Nice Holystone, he informs Rail that the bomber has since moved from Chicago to New York City.
Graham and Carol both recognize each other from the train robbery, leading Graham to speculate that Carol and Gustav might be Huey Laforet's servants Sickle and the Poet rather than so-called reporters. While Graham is wrong about Gustav and Carol, Rail and Frank are two of the people he is looking for, and they thank Carol and Gustav for lunch. Before they leave with Graham, Rail warns Carol to leave Chicago as soon as possible, alluding to a large explosion in the future.
Alone once more, Gustav declares that he and Carol must stay in Chicago a while longer. He has predicted that "certain events" will take place in the city, and believes that they have time before their departure to enter the fray themselves.
The two are joined on their bench by a main named Klik, who forces them at gunpoint to accompany him to the Russo Family mansion. There, don Placido Russo demands to know how a couple of news reporters are connected to Rail and Frank. Gustav's explanation that the four of them became acquainted that very day is not to Placido's liking, so Gustav suggests that Placido contact his parent company if he wants to verify their identities. If he wants to know more about the two persons that Gustav and Carol had lunch with, then all he has to do is request an official meeting with Gustav acting as an information broker.
Placido smiles derisively at the title 'information broker', while Klik warns Gustav against thinking that he can "take the high hat" simply because he thinks he knows more than they do. Once Klik settles down, Gustav agrees that what he and Carol knows is limited. For example: when Placido's nephew Ladd was arrested back at the tail end of 1931, the white suit Ladd been wearing at the time had previously belonged to Placido. It had not escaped the police officers' attention that the name embroidered on the suit was not Ladd's own, and they prepared to investigate Placido's involvement. After all – if Placido had indeed loaned Ladd his suit, then perhaps he had foreknowledge of Ladd's train heist.
Placido is no longer smiling at this revelation, and he grinds out, "Who...who the hell are you?" Gustav repeats his introduction, and asks that Placido forgive his earlier conduct. If Gustav had not given proof of his knowledge as an information broker, then there was little chance that Placido would have believed him. He then objects to Placido's accusation that he is stealing information to use as blackmail.
Placido reveals that the day before Ladd's arrest, someone had stolen a huge amount of money from the Russos. What is more, a group of delinquents had put down one of Placido's best men. Placido knows that the "nancy boy" who killed his man is called Jacuzzi Splot, but is at a loss as to who stole his month's profit. He questions whether Gustav can so easily gives him the facts he is after, even when no one else has any leads. Gustav smoothly advises that they discuss payment first.
With the deal made, Gustav identifies the robbers as Isaac Dian and Miria Harvent - a couple who later became acquainted with Jacuzzi Splot. Still suspicious of Gustav's integrity, Placido decides that Gustav and Carol must stay at the manor as his guests for a few days until they find Rail and Frank.
Carol protests the idea of involuntary confinement and questions Placido's intentions for Rail and Frank; Placido, unmoved, tells Gustav that he will separate him and Carol for the time being in order to prevent any funny business. So saying, he orders Klik to put Gustav in a random room and lock Carol up with Lua Klein.
Gustav is led to a room, where he remains until one or more of the Russo henchman fetch him and take him back to Placido's office. Placido asks him if he knows anything; Gustav replies that he is not only unsure what Placido wants from him, he wonders how Placido would have him proceed when he has been severed from his sources. Placido brusquely gives Gustav permission to reattach himself to said sources, and reminds him that the Russos still have Carol and her camera. Gustav makes a brisk exit from the premises.
Once Gustav gathers the pertinent information, he calls Placido and says he has found an urgent piece of relevant information which, although unrelated to the Lamia's whereabouts, is far more immediately important. He then advises Placido to flee Illinois at once and trust no one if he wants to live.
Placido demands an explanation, a demand which Gustav ignores. He announces his intention to collect Carol in short order, and that he will be happy to give Placido a full report should Placido still be in the vicinity. So saying, he ends the call and returns at once to the mansion, where he reunites with Carol in Lua's quarters.
Gustav, Carol, and Lua take off running through the hallways, and though an explosion and gunfire rock the walls, are able to escape the manor together via Gustav's leadership. With all the hotels and train stations likely under surveillance, and without an automobile, they are effectively trapped in Chicago for the time being.
Having few other options available to them, they meet with Muybridge in his Nebula office and explain their circumstances. Muybridge agrees that it would best that the three of them stay in the building for the time being – an offer that is not purely altruistic, as Gustav has promised him 'priceless information' in return for his assistance.
After Muybridge recounts a story of how he was nearly murdered by Ladd in the office they are sitting in, he determines that the staff's living quarters are likely the best place for them to hide. He says that any future questions they have ought to be directed to "this fellow" from Security, indicating a dour man standing by a nearby pillar. As the employee used to work for the Runorata Family, he ought to have an idea of the sorts of mafia tricks the Russos might try to inflict on the trio. The man offers them a slow nod, chewing sugarcubes all the while.
Gustav and the others are led to the guest rooms, where they stay undisturbed for some time. Eventually, Gustav steps outside to admire the art in the corridor – and thus catches sight of a group of men exiting the elevator. They walk much like predators - or at least, corporate joes, but Gustav's attention is drawn to one of them in particular. Muttering to himself, "He...why would he be here?", he watches the group for a moment longer before reentering the guest room to place a telephone call.
Once he reemerges in the corridor with Carol in tow, he remarks to the group's leader – the man he recognized – that it has been a long time since they last met. The other man, agreeing, asks if Gustav is here on business; Gustav demurs that he thought he might have spotted him yesterday, so he thought it only polite to greet him now. The man acknowledges that they do need to discuss some matters...but it will have to wait until after lunch.
Once the group of men are out of sight, Gustav awards Carol 30 points for "staying silent and panicking." However, when Carol asks if the men were Mafia, he deducts 527 points on account of her fearing someone whose identity she did not actually know. He then explains that the man he spoke with was Bartolo Runorata, the head of one of the most powerful mafia families on the East Coast.
At some point while they are in the conference room corridor, Carol asks Gustav what is going on. In lieu of answering, Gustav remarks that the art on the wall is Carnald's work, as was the art by the front entrance (see Trivia). Then, he relents and says that Renee and the Runoratas do not have ties to each other - whether Renee has arrived to offer them an alliance or trouble is at present unclear.
Carol wonders if Renee is making some sort of drug (given that the Runoratas are heavily involved with drugs), and Gustav awards her 1295 points for an excellent, if ultimately wrong guess. It would take too long to explain the details in full, he says, but she probably ought to understand the basic gist before they take lunch with Bartolo himself. She is terrified at the thought of lunching with Bartolo, but Gustav reminds her that the entire purpose of this trip was to introduce her to their clients.
An explosion rumbles the floor below them – and more explosions follow.
Fire bursts through the corridor; as Gustav drags Carol behind a column, they see several the shape of several people emerge from the smoke – including Rail – and join the group in heading for the rooftop garden. Once on the roof, Rail thanks Carol and climbs over the rooftop railing. They prime a bomb and drop it, and let go of the railing in attempt to follow suit.
Jacuzzi manages to grab Rail's hand in the nick of time, and Nice grabs his hand while Miria grabs Rail's. When Miria's grip begins to slip, Gustav and the others race toward the guardrail in the futile hope that they will reach her in time – but Isaac, appears as if out of thin air in order to do just that.
In the aftermath of the incident, Gustav and Carol dine with Bartolo and his mafiosi at an upscale restaurant - though Carol, unlike Gustav, hardly had an appetite in the face of such dangerous men. Though Gustav and Carol have already bought their departure tickets, they are to stay in Chicago for a few more days to scout out the general situation. Once they part ways with the Runoratas, they return to the Gunslack Hotel and find police congregating on the corners of the hotel's street.
As they enter the hall, Carol mutters to herself that Gustav's ability to speak to anyone - mafiosi, politicians, businessmen included - borders on the unnatural. Gustav overhears and asks her whom she would actually be capable of talking to, and Carol recalls a man whose eye was bandaged - innocently unaware that the man in question was actually Huey Laforet. Gustav, despite knowing the identity whom she speaks, says nothing.
Carol is sure that the bandaged man must be important and thinks they should try to chase after him. Gustav asks if she does not think it would be dangerous, but says he will not stop her – though he warns that things are not as simple as she believes they will be.
Flustered, Carol insists that she knows they are not simple - though she stutters that, since the man was handsome, all the other girls who will probably be trying to get his attention will make her job harder. Gustav briefly considers telling her the truth about Huey, but instead opines that the events in Chicago reek of Sham and Hilton - and he is sure that Sham will contact him soon enough.
Gustav and Carol return to New York's Pennsylvania Station via the transcontinental railway later on, with Carol's excitement over being home contrasting Gustav's more staid demeanor. They engage in spirited conversation as Gustav exits onto the platform; when Carol suggests that their lives are determined by speed, Gustav uses the opportunity to launch into a speech on what determines their lives as reporters.
When Carol points to a woman behind Gustav, Gustav reminds her that it is rude for a lady to point (while jabbing his own finger at her). The hypocrisy is less important than the fact that they are the only ones who are supposed to be on this assignment, and Carol asks the woman who she is. Once Gustav turns to look, the woman identifies him by name and occupation.
The woman says that she has heard the Daily Days can acquire all sorts of intelligence, prompting Gustav to expound in great detail upon their organization's policies, prices, and the difficulty of the field. She reacts just as he has expected: with a soft smile and a repeat of her first greeting, she pulls a gun out of her bag and aims it at Gustav's chest.
With nary a reaction, Gustav affirms that as the woman is clearly not a customer, they both need not be civil any longer. He steps in front of Carol so as to shield her, asks the 'robber' why she is risking arrest in order to steal information from them, and expresses a desire for the robber's name. Without hesitation, she introduces herself as "Hilton, one of the Twins." As it turns out, Gustav already knew she was Hilton, but what he meant was that he wants a more 'specific' name. Hilton retorts that this is exactly the quality in Gustav that she finds intolerable – his ability to "see through everything" – and asks how much Gustav knows about "Us, about [her]."
After a flurry of semantics, Hilton clarifies that she wants to know why Huey's left eye was taken, what happened in places that she or Sham were not present, and more besides. Gustav replies that since Hilton is essentially mugging him for information, he will not hesitate to tell her everything. His eyes blazing, he suggests to Hilton that they relocate before they catch the guards' attention; she agrees, but warns him against any escape attempts. Unruffled, he advises her to 'prepare' herself for his information, and asks that she not come crawling back to him if events turn sour.
He proceeds to relate to Hilton the events that occurred in Chicago.
- "St. Germain" is a pseudonym that Gustav borrowed from "the famous immortal alchemist and peerless information broker," the Count of St. Germain. His real surname is unknown.
- According to his character sheet, he has an eidetic memory. This tidbit is not brought up in the novels.
- A short story written by Ryohgo Narita for the 電撃文庫総合目録2006 SPECIAL EDITION (Dengeki Paperback Comprehensive Catalog 2006 SPECIAL EDITION) features one "Theodore St. Germain," a twenty-first century information broker who took his name from 'an ancestor'. It is likely that Narita was referencing Gustav, especially since the light novels which first reference Gustav were published in the last three months of 2006. Thus far, there has been no reference to this potential descendant in the light novels themselves.
- Theodore's dialogue in this short story is highly reminiscent of Gustav's discussion of story beginnings, endings, and main characters in Episode 01, which would air in July 2007.
- An eccentric, mysterious, and seemingly strangely omniscient character also named St. Germain makes a brief appearance in the fourth volume of the Fate/strange fake light novel series, also written by Narita. It is possible that this St. Germain's name is a reference to Gustav.
- Gustav, as voiced by Norio Wakamoto, features in the Prologue track of Spiral Melodies.
- The "Carnald" that Gustav references in 1934 is in fact Carnald Strassburg, a famous artist and inventor from the fictional island of Growerth. Growerth is the setting of Vamp!, another light novel series set in the Naritaverse.