Lulu

Lulu was a British woman living in London at the time of the Victorian era.

At some point in 1868, Lulu came into contact with Trevor Alton, a doctor with a multiple-personality disorder, who successfully seduced her. When she later saw Prudence Browne kissing Alton in the park, she became enraged and confronted the woman in the street, claiming that he belonged to her. Eventually, Prudence managed to slip away from the woman.

The following morning, Prudence was found murdered in the local park, and Lulu, waiting to confront her again outside her house, was confronted by the Assassins Evie and Jacob Frye, who were trying to solve the murder. Lulu told them everything that had happened, before pointing them into the direction of Baxter's house, where the Frye twins found the clues they needed to solve the murder.

Reference

 * Assassin's Creed: Syndicate - The Dreadful Crimes