- "I'll be buggered if we'll permit our nephew to die like some commoner who slips in the bath. Not without a fight."
- ―Lavinia Fairweather[src]
Lavinia Fairweather, also known as Vin, was a witch and the sister of Sophronia and Edna, and the great aunt of Rupert Giles. Unlike their sister Edna, Sophie and Lavinia didn't join the Watchers' Council and chose instead to use their talent for magic to preserve their youth and pursue hedonistic, carefree lives.
By the time their grandnephew Rupert was a young boy dreaming of becoming a fighter pilot, Sophie and Lavinia approached Edna and her son to ask them for the Shard of Stronnos, a mystical artifact that could convert matter into energy and viceversa, so they could restore their lovers, which an unidentified light demon had transformed into beings of light and trapped in mirrors.
Edna gave the Shard to Sophie and Lavinia after young Rupert intervened and inadvertently made the light demon corporeal, and vulnerable to be killed.
End of Magic
Decades later, following the end of magic, Sophie and Lavinia sought the help of Angel and Faith to protect them from a large number of demons with whom they had made deals to remain eternally young, beautiful and athletic. The end of magic gave these demons the chance to demand the debts to be payed.
The two had also heard of Angel's plans for resurrecting Rupert and used the Shard, which they had kept for decades, to restore a Rupert's essence as a child and his innocence, which, according to Lavinia, he had lost the moment he activated the Shard's power.
Sophie and Lavinia stayed at Rupert's manor, though each of them had a different agenda. While Lavinia supported Angel's plan to resurrect Rupert, whom she considered necessary for the world, Sophie feared the possible consequences of Angel's plan and told Faith to stop the vampire should he go too far.
Both Sophie and Lavinia also became acquainted with Willow Rosenberg during her time with Giles and the Devon Coven while she was recovering from her addiction to dark magic. Left behind while Angel and the gang venture on a journey to Quor'toth, Sophie and Lavinia where met by Whistler, Pearl and Nash. Looking for Angel, Whistler tells them to have Angel meet him when he comes back. 
- Women of a Certain Age
- Family Reunion, Part One
- Family Reunion, Part Two
- Family Reunion, Part Three
- Death and Consequences, Part One
- Death and Consequences, Part Two
- Wonderland, Part Four (only in visions)
- Spike and Faith
- What You Want, Not What You Need, Part One
- What You Want, Not What You Need, Part Two
- What You Want, Not What You Need, Part Three
- What You Want, Not What You Need, Part Four
Behind the Scenes
- Lavinia, along with Sophie, was originally intended to appear in Joss Whedon's planned, but aborted, Ripper spin-off, and would ideally have been played by one of Anthony Stewart Head's daughters. Based on likeness, she would appear to be modeled on Daisy Head.