What an amazing thread.
The Actress
Twenty years ago, Lady P___ was an actress of the lowest sort, and a sometimes singer in music halls. Then she caught the eye of a handsome member of the gentry who devised a plan. She was taken off to a distant school and trained in the arts of the well-mannered, and returned with a flawless accent and impeccable table manners. Unfortunately, no-one thought to do anything about the little tattoo in the small of her back.
She was spied upon in her bath by a rogue and when she arose, he almost fell off the roof. That mark was known to him! It belonged to his lover of long ago, who left him in dire straits. Now, he's come 'round to demand compensation on a weekly basis or else he'll talk. Lady P____ has come to love her husband and the high life and if it were known she were a dance-hall girl, her position would be ruined and her husband's family scandalized. Using her old tricks of disquise, she finds out where the rogue lives, and she plots murder. Knowing little of the art herself save poison and knowing that someone found dead by 'womanly arts' could lead back to herself, she enlists the aid of the rogue's apprentice by the simple act of seducing the young man. Once he is deeply in love with her, she coaxes him to murder the rogue in a brutal fashion so that no suspicion falls upon herself.
Then she is given cause to beleive that the rogue passed on his knowledge. Again and again she sends the young man out to kill those she thinks know her secret. As these random people begin to die, will the party figure out their 20-year-old connection and stop the killings?
Added spice: (1) The young apprentice is Lady P____'s son by the rogue, long thought dead of fever. Despite their lovemaking he has never seen the mark but knows of it. He returns to her one night as she is dressing, and sees it. Realizing what he's been doing, he slowly goes mad. (2) The theater company did very well for itself in the last several years and moved up in society a little; they now perform in nice playhouses, turning the young man's murders into a 'Phantom of the Opera'-esque plot.
The Cobbler
Old Meechum the Cobbler has the most wonderful shoes and gloves. Coming from poor origins, he's attained a place in the nice area of the trade district and is known to all as a humble, pious soul who always has a kind word for everyone and gives his extra pennies to the poor, even though he barely gets by himself. He's been getting attention lately, since he's come upon a new means of tanning leather, a method that makes gloves as soft as silk and shoes as comfortable as slippers. He guards his secret carefully and there are several who would love to know how he does it. He's started to attract clients of good renown and there is talk that he might even be give a Royal Monopoly on certain types of gloves, which would as good as drive several of his competitors to ruin.
Several of those competitors pool their money and hire someone (a member of the party) to break into the man's workshop and discover his secret. They find... nothing, just the normal tools of the trade. Not even notes on a new process.
Meanwhile, the body of a prostitute is pulled from the canal. A sad thing, but they get drunk and slip into the water sometimes. Then they notice a curious thing: her back has two strips of flesh missing, in the shape of a pair of gloves....
The Orphans
The Orlake Orphanage has a good reputation: tough but fair. They take the cases no-one else wants and makes model citizens out of them. They boast that their children always go to the best homes, and none are sold for labor. Mr Orlake scours the streets for runaways and takes them into his own home he does, a huge and rambling mansion on the outskirts of town. Not a week goes by that a new child doesn't arrive.
Mr Orlake is a master of psychology and torture. His father was a doctor who was ruined in his profession by the thoughtless actions of a child of the Quality, and he's decided to take his revenge. His father passed on knowledge of many exotic drugs to him; he uses these and sadistic methods best not described to break a child's mind and spirit, then remold him into something more appealing. Once the boy or girl has been rendered 'fit', they move from the basement warrens into the fabulous upper mansion. They are presented to childless couples of the Quality, or sold discreetly to those of the nobility who might want a 'spare'.
Once ensconsed in their new abode, the child is quiet and polite and grateful. He is also an expert spy who uncovers blackmail material and sends it to Orlake. He is a dagger aimed right at the heart of the family, and hopefully can remain a secret thorn in their side for years.
No amount of conditioning lasts forever, though, and despite visits from Orlake to check up on 'his darlings', some of them are starting to 'fray' at the edges, betraying the madness that lies just below the surface. If they do break down all the way, they become the savage flesh-craving little monsters they were in the warrens.
Extra Spice: (1) Orlake secretly works for the government, trying to develop 'the perfect weapon', a child that can be insinuated into the noble family of a rival kingdom and eventually deliver that throne to his masters. (2) Orlake's medicines are made from people, specifically 'failed' children. (3) Some of Orlake's orphans have shaken off their conditioning and are banding together in order to kill Orlake.