Jenny Flint

Jenny Flint was the companion to (and maid of) the Silurian Madame Vastra. They operated from London in the late 19th century. Jenny and Vastra were romantically involved with one another.

Biography
Jenny initially worked as a match girl. She first met Vastra when she was attacked and molested by the Tongs. Vastra decided to hire Jenny as her maid, companion and romantic partner.

Among the many allies the Doctor had recruited, she along with her lover were among the few to survive the attack of the headless monks. She displayed excellent skills with a sword during the battle. She comforted Amy Pond afterwards, and later returned to her own time with Vastra. (TV: A Good Man Goes to War)

Personality
Jenny was a lesbian or at least bisexual and had a romantic relationship with Vastra despite the fact that they were different species. She showed jealousy when Vastra showed interest in others. Jenny was also quite sarcastic at times which was shown when she said, "Thank you," when Vastra commented that mammals all looked alike.

She survived the battle of Demons Run without any injury. Despite being a warrior, Jenny was also compassionate and comforted Amy about the loss of her child. She also told Amy that it wasn't the Doctor's fault that Melody Pond had been kidnapped. (TV: A Good Man Goes to War)

Spin-off?
Since their first appearance, Vastra and Jenny became popular characters in fandom, with fans wishing for a spin-off series to be made based on their adventures. Steven Moffat addressed this, saying that he considered making a spin-off when he created the two characters, but wouldn't have the time, though he said he would like to revisit them.

The Brilliant Book 2012
According to The Brilliant Book 2012, a book that contains non-narrative based information,
 * On one occasion, Jenny helped the Doctor defeat a Kraal plot to replace Prince Bertie with an android duplicate while Vastra was in Egypt.
 * At one point, she and Vastra battled a CyberNeomorph.
 * Following their return to their own time, Vastra and Jenny were added to the Papal Mainframe "most wanted" list.