Shemeshka the Marauder is an important Arcanoloth/Raavasta denizen of Sigil in the Dungeons & Dragons campaign setting of Planescape. Also known as the King of the Crosstrade, Shemeshka leads and directs one of Sigil's greatest networks of spies, informants, thieves and assassins, making her one of the most powerful women in the city.
Despite this, she is best known for appearing to be a vainglorious, frivolous, almost vapidly cruel and mercurial figure, who parades around the city with a small army of sycophants who constantly keep her looking tidy and praising her beauty, even lugging around a large mirror. This appearance is at least partially staged; for example, her attendants are skilled assassin-warriors who leap to her defense if needed or slip away to murder those she indicates, whilst the mirror is actually a powerful artifact, with the ability to spy on any individual she wants no matter their position in the multiverse being only one of its many powers.
Such is Shemeshka's arrogance that she makes no secret of her true nature, and as far as anyone knows never changes out of her true form of a humanoid fox/jackal. She even goes so far as to wear an ornate "crown" made of the blade-sharp razorvine that grows rampant throughout Sigil, which more than one individual has suggested may be in mockery of the Lady of Pain. Mind you, she can also yank a strand out of her "crown" and turn it into a lethal whip in battle, so it's perfectly practical as well.
One particular aspect of Shemeshka that ensures she will never be forgotten by the fandom, if only due to sheer incredulity, is a little detail from her writeup in "Uncaged: Faces of Sigil". There, despite her being constantly referred to with feminine pronouns, her profile features a male symbol as its gender marker. Thus, Shemeshka is in fact a man who dresses up as and tries to pass himself off as a woman... or, rather, she was, until "Faces of Evil: The Fiends" came out and revealed that Arcanoloths, as high-level Yugoloths, are hermaphroditic - Shemeshka is a girl, alright, it's just that she's a dickgirl. In-universe, asking her why she's called the King of the Crosstrade when she's a woman will greatly upset her, and she'll make her displeasure known.
Shemeshka's web of contacts, pawns, victims and enemies is quite vast, and even she isn't aware of some of the people caught in it. Most notably, she's completely unaware that her most trusted assassin-valet is in fact a mad Rilmani named Jemorille, who was exiled to Sigil for his utter incompetence at keeping the balance and his arrogant inability to admit he was, in fact, a total idiot. Jemorille thus exploits his position to continue his deranged manipulations of people in Sigil, all for the nebulous goal of "preserving the Balance".
Another figure of note is a tiefling tout (a tour guide of sorts in Sigil) named Kylie, who constantly challenges Shemeshka's authority and has yet to be punished for it. Indeed, Shemeshka has actually called in a debt owed to her by Autochon the Bellringer, Kylie's old boss on whom she turned stag, to protect Kylie and making sure her arrogant stupidity doesn't get her killed. Some have suggested that this may be because Kylie is actually Shemeshka's unacknowledged daughter, the result of a liason between the fiend and an unknown human man.
Taking the above into account and whether it triggers your nightmares or your Magical Realm is a good indication of how much of a /d/eviant you've become. There's also a surprising amount of fanart to be found of her online.
What Did 4e Do?
Actually, Shemeshka profited from the 4e changeover. First mentioned in the Dungeon Master's Guide 2, it's stated that with the fall of the factions, Shemeshka has united with Zadara and Estavan to form the Mutual Trade Association. Not only is this group perhaps the most important political mover-and-shaker in all of post-Faction War Sigil, but Shemeshka herself has been firmly established as the unofficial leader of the group. For all practical extents and purposes, Shemeshka runs Sigil as much as anyone who isn't the Lady can be said to do so.
She also got her own Demonomicon of Iggwilv article in Dungeon Magazine #205. Here, it mentioned some of the mysterious broker's possible pasts, such as having originally been sent to Sigil as a representative of Phraxus only to betray him, or to be the unwanted and abandoned child of the legendary raavasta (arcanoloth) sorceress Larsdana Ap Neut. It also discusses some of her many contacts and enemies of this edition; A'kin the Friendly Fiend (a raavasta that runs a magical item shop), the ultrodemon Archdegog Kaugothirn, the oni Estavan the Merchant Lord, Ramander the Wise (a portal-mapping human wizard who was Mazed, which she used to steal his logbook), Satugla the Grand Assessor (a powerful raavasta merchant lord from the Abyssal boom-town of Morglon-Daar), and Shylara the Manged (a raavasta ex-student and lesbian lover of Shemeshka's, whom she cursed with incurable mange after dismissing her).