Violetta Mondarev is a trained Smoke Knight and apparently a fairly experienced adventurer. Her last name was first revealed in a cast list included with one of the strip's printed volumes, and (much) later confirmed .
She is related by blood to Tarvek Sturmvoraus, though the exact nature of this relation (apparently some sort of ) is unclear, and she has been assigned/trained since birth to be his bodyguard and protector. When first introduced during Agatha's visit to Castle Heterodyne, she displays a great deal of animosity directed at him, primarily for forcing her back into some sort of active duty, for which she says she has no affinity whatsoever, but also for being an all around (according to her, anyway) annoyingly useless and suicidal nitwit. Nonetheless, and despite her contrariwise attitude, she follows her duty and does everything she can to keep him alive.
Her bag of tricks includes the same kind of grapnel gun as used by Veilchen much earlier. This may or may not mean that Veilchen, too, is/was a Smoke Knight, particularly given their apparent links to House Sturmvoraus. She also displays a wide knowledge of (and some immunity to) various poisons and stimulants, which she often dispenses via a small blowgun, and is pretty handy with a blackjack when needed.
In releasing her to House Heterodyne upon the possibility of his impending death, Tarvek reveals that he is a member of The Order and that her position is directly in fealty to them. He also reveals that he, himself, as "King" (presumably the Storm King) is still under authority of The Order. Following this release, Violetta immediately becomes a loyal and enthusiastic minion for Agatha.
Although Violetta is aware of her own incompetence as a security operative, she is never made aware that that incompetence extends to being unable to follow her own suspicions and actually deduce the merely figurehead role of the Mechanicsburgermeister despite being his secretary for an extended period of time.
Adventures with Agatha
Her on-screen actions cast some doubt on Violetta´s self-description as incompetent. She is at least good enough in misdirection and sleight-of-hand to remove Theo DuMedd from Agatha´s grasp and replace him with a properly-attired life-size doll, without Lucrezia, then the dominant occupant of Agatha´s body, noticing until two panels after the fact. (The novel version of this scene features a more realistic but still impressive Theo-sized bundle of cloth and twine.) She pulls this same trick on Zola, exchanging Zeetha's sword for a flower,  and leaves Vole holding a broom instead of a gun. And much later, she surprises Tweedle, switching Agatha's Wasp eater with a smoke bomb while he is looking at her. This, in turn, poses an interesting (and perhaps disquieting) question: if Violetta is a rather incompetent Smoke Knight, what kind of tricks do the really competent ones have up their figurative sleeves? It should be noted that at least in Tweedle's opinion, Violetta's skills have vastly improved over what she displayed in the past.
During the Castle Heterodyne plot-arc, she shows at least the beginnings of a romantic interest in Moloch Von Zinzer; when the Siege of Mechanicsburg begins, she fights various attackers of the city with Zeetha in an attempt to impress him.
Following the breaking of the Siege, Violetta accompanies Krosp, Agatha and Tweedle on their chaotic plunge through the obelisk portal under the Red Cathedral, and has remained by Agatha's side through a perilous escape in snowy weather, a humble monk turned assassin, an Old Heterodyne's idea of a useful gift, (showing the aforementioned skill with a in the process) and Agatha's eventful visit to Paris and its underworld.
Then on to England. While staying in the undersea dome of the Queen's Society, it's revealed that Violetta's long association with Tarvek has given her a Also, she Lady Ariadne Steelgarter snooping in Zeetha's things, resulting in a bloody off-screen fight between the two women. Steelgarter claims to her various allies that this fight results in Violetta's death, but not terribly surprisingly, it eventually turns out that our favorite Smoke Knight is still alive and kicking, and has been into serving as the official chained-up sacrifice/distraction for Red the Extradimensional Being that the Grey Hood conspiracy summons into the temple beneath the Society's dome. In the chaos of said Being's arrival, she is rescued from the summoning equipment by Oggie and Higgs, leaving her alive but stuck for an extended period in a rather embarrassing outfit.
She finally gets her uniform and equipment back, just in time to help with the "extract Lucrezia from Agatha's brain" project. She strings some traps for the various invading squads of wasped British soldiers, but suffers a hand-stabbing when she gets too close as Lucrezia-in-Agatha runs amok with one of Zeetha's purloined swords. This prompts Violetta to down a dose of "Montebaarg's Beef Boy Elixir" which bulks her up physically, allowing her to help the newly en-Queened Lu. She evidently survives this without serious side effects, and finally gets to wear a pretty dress at Queen Albia's welcome-home party.
Big Rat Island, where she manages to get the best of fellow Smoke Knight Madwa Korel by of Prende's Chronometric Lantern and Taking possession of the Lantern, she later the Francisia Monahan and robotic copy of Lucrezia until Agatha can She also to a fleeing Steelgarter while trapping her in the Lantern's power, the exact nature of which is yet to be revealed.to
If the "Mechanicsburg Solstice" flash-forward story is indeed 100% canon, it has been confirmed that she will survive the Other War and continue to serve Agatha as the latter woman takes up her duties as ruler of a freed Mechanicsburg.
The version of Violetta who appears in the Girl Genius print novels is pretty much the same as we see in the comic. At the very end of Agatha H. and the Siege of Mechanicsburg, as Agatha makes her triumphant procession to the Red Cathedral, Violetta and Moloch do get an extra scene together; he announces his plan to leave the city immediately, and tentatively asks her to come with him. She of course refuses, and after Ognian "accidentally" pushes them into an embrace, Moloch agrees to stay one more day.
Possibly relevant outside information
"Violetta" means "violet", just like "Veilchen" does - only, in this case, in Italian instead of German.
Most real-world stage magic is, in fact, nothing but "misdirection and sleight-of-hand", yet its practitioners are capable of a number of astounding feats that the uninformed have no way of explaining if they are not in on it. The part of stage magic which is not nothing but misdirection and sleight-of-hand is instead misdirection and sleight-of-hand plus some fancy clever gadgets - a category of equipment which, one must presume, the story's Smoke Knights probably have some access to, as they serve a line of powerful Sparks.
Purple smoke is used by the military to mark places where rapid egress is required--or at least it was in Vietnam.