O (The Furies)

O was a clone of River Song.

She was part of a second batch of clones created by Madame Kovarian after River failed to kill the Eleventh Doctor at Lake Silencio. Like River and her fellow clones, O was raised on bedtime stories about the Furies and trained to be an assassin. She grew up considering Kovarian to be her mother and believed Kovarian's promise to give her a proper name after her first mission. However, as soon as she realized River wasn't responsible for H-One's death, she agreed to join forces with River against Kovarian. Kovarian unsuccessfully tried to sway her by saying she was planning to name her Flumen. After Kovarian was defeated and the, O chose to stay with Brooke 2 and H-Two so they could torture Kovarian until she either died or they could find a way around their neural blocks to personally kill her themselves. (AUDIO: The Furies)