Shemeshka
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 network 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.
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.
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 named Kylie, who constantly challenges Shemeshka's authority and has yet to be punished for it. Indeed, Shemeshka has actually assigned one of her minions, Autochon the Bellringer, the task of protecting 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.