Octavia Plumb

Octavia Plumb (unknown – 1868) was a British Templar and one of the seven gang leaders that controlled all of London's boroughs around 1868.

The leader of the Blighters in the Southwark borough, she was at some point tracked down and assassinated by the Assassins, who sought to seize control of the gangs and take back the city.

Reference

 * Gamereactor.eu: Assassin's Creed: Syndicate – PS4 gameplay – Freeroam with Jacob (3.55)