Lady Sybil Ramkin is first introduced in Guards! Guards!. She is a large, rather Wagnerian and aristocratic lady, almost as frightening as the swamp dragon that she breeds, yet also a kind-hearted person who tries to show compassion for others. She is known to be able to like almost anyone, and accept anything with great grace.
She was born into the wealthiest family in Ankh-Morpork and resides in the most select part of Ankh, Scoone Avenue. She has a dragon pen outside her house where she breeds and cares for swamp dragons. She also supports The Sunshine Sanctuary for sick, abused or abandoned swamp dragons in the city, which is run by her friend Rosie Devant-Molei. Her hobby has left her with her natural hair singed off and she wears a wig in nearly all circumstances.
Her maiden name is quite apt - a Ramekin is a small dish used to prepare and serve desserts like Crème Brûlée. The ramekin is built to withstand extreme heat, such as the flare of a torch used to light the Crème Brûlée - or a blast of fire from a dragon, an occupational hazard for dragon conservationists like Lady Sybil.
Despite her high-class upbringing she has displayed a resourcefulness (including an instance where she attacked abductors looking for a sacrifice) that attracted the attention of Sam Vimes, the Commander of the Ankh-Morpork City Watch, to whom she is currently married. The pattern of Sam and Sybil's marriage was set the moment he turned away from his wedding to chase an assassin who had just made an attempt on the Patrician's life. Lady Sybil is a remarkably patient woman; she spent nearly the entirety of The Fifth Elephant attempting to inform her increasingly distracted husband that she was pregnant with their first child. It is clear that Vimes loves his wife dearly, indeed when he was trapped in the past during the events of Night Watch, alone in a world he no longer recognised, the History Monks gave him a silver cigar case his wife had bought him to inspire him to continue with his mission. However, it is not entirely clear whether his hatred of crime and the evil of humanity is greater than his love for his wife. Sybil bears this divided loyalty with some grace; however, nearly every Watch novel concludes with Sam making some form of amends to his neglected wife, either a delayed honeymoon, or simply time alone with their new baby.
Sybil's actions as a wife are more to do with a sense of duty and tradition than with necessity; she doesn't need to cook, as she has a phalanx of servants to do so for her, and yet she cooks for her husband because she believes that is what wives do.
She can't cook in any meaningful sense; her typical output consists of leathery fried eggs, black and crunchy potatoes, and bacon that tends to shatter - all cooked on a pan held above a flaming dragon (and left there for too long), but that suits Sam, accustomed as he is to late nights outside low-cost greasy spoons.
Sybil also darns her husband's socks (she is far too genteel to damn them), even though she is rich enough to ensure he never need wear the same pair twice in his life, and as a result they no longer fit his feet properly, though he doesn't have the heart to tell her.
She donated her childhood home, Pseudopolis Yard, to the Watch after their original headquarters was burnt by a dragon.
She is an amateur soprano, and also enjoys spending time with Vimes when he is not on the job (which is very rare because there is always crime in Ankh-Morpork and crime does not take a rest whenever Vimes does).
Sybil maintains a number of close (female) social contacts from her school days, which, thanks to the kind of school she went to (The Quirm College for Young Ladies), are now strategically placed in the highest levels of power across the Sto Plains and often more powerful than Ankh-Morpork Guild leaders. Vimes once conjectures that if they so conspired, they could run the world, if they don't already.
Since Night Watch, she has a son with her husband Sam, called Young Sam. The birth was traumatic and nearly led to her death, but she was saved by the intervention of Doctor Lawn. After receiving an astronomical fee for this service, Lawn went on to found the Lady Sybil Free Hospital.
Her name was twice misspelled as Sibyl in Thud!