Sid and Sadie Smithfield-Wyatt were Shades twins who "died" in an occultist ritual in 1977. Their deaths appeared to be a double suicide. Jane Quaint took over their house and continued their work after their demise.
Sid and Sadie are said to wear mostly the same clothes and look outrageously identical, even though they are fraternal twins. They wear odd clothing and makeup, and speak in a posh British dialect. The two of them "died" in their early twenties, so it is safe to assume that they appear that way in the novels.
Little is known about Sid and Sadie's background. It is said they grew up in a wealthy family until their parents died in a car crash, from which they survived and gained the Sight. The twins inherited their family's money at a young age and traveled the world in search of a way to "defeat death." They later bought a house in which they recruited Jane and others to help them do so. A ritual was performed by them and their followers in 1977, which kept them both in a death-like coma until The Shadow Cabinet.
The Shadow Cabinet Edit
Sadie is described as willowy, fairy-like young woman with "feathery blonde hair." Her eyebrows are so pale they appear invisible, and she is dressed in a long white gown. Egg blue eye shadow covers her eyes, and she also has a crescent moon drawn on her forehead.
Sadie is shown to be clever and quick, in both humor and intelligence. She seems to be the smarter of the twins and is harder to distract than Sid. Sadie also has no fear of death or pain, as shown when she easily pried a knife from her neck with her fingers, slicing them in the process. She is kind and friendly to everyone, a skill she uses to manipulate people into cooperating with her. Murder is not beneath her either: she has nonchalantly discussed and performed mass murder on acquaintances (by poison).
Sidney "Sid" Edit
Sid is tall, blonde, and wears a fedora. He appears nearly identical to his sister, though they are only fraternal twins. He also wears odd blue makeup.
Sid is the more playful twin; he has flirtatiously teased both Rory and Stephen. He is quick-humored and smart like his sister, though Sadie's focused demeanor could peg her as the brains of the bunch. Sid had also assisted in a mass poisoning, slit Jane's throat, and (possibly) staged the car crash that killed his parents. Both twins posses superhuman abilities.
After the siblings' ostensible suicide, their bodies remained intact for decades while they lingered somewhere between life and death. In The Shadow Cabinet, Jane Quaint forces Rory to take part in a ritual that allowed Sadie and Sid to return to the realm of the living.