Who is the girl at the end of The Equalizer?

Can you clarify for me who exactly is the girl that appears at the end of The Equalizer? Is she a new character introduced in the film, or does she have some connection to the main protagonist or other characters we've seen throughout the movie? Also, can you provide any insight into her role in the film's plot or how her appearance may impact the story moving forward? I'm intrigued by her inclusion and would love to know more.