Rue

Rue is a cryptic, but significant NPC (and in the Equinox Update, a temporarily playable character) located in a room in the back alley of Refuge, to the right of the Lamplighter's house. She also features in one of the three visions Niko can encounter during their travels.

Background
So far, little is known of Rue; other than the fact that she has seems to know to The Author, and that she was one of the 4 characters that existed in the Old World.

Personality
Rue, similar to Niko, is kindhearted and caring, talking to Niko in a friendly manner even though they usually don't remember her. After the Equinox Update, she is also shown to be obedient and loyal as she followed the Author's written advice despite such likely causing her loneliness.

Trivia

 * Rue's name is only found out - at minimum - in the second run (or NG+).
 * Her in-game dialogue (before the Equinox Update) changes during the first 4 runs.
 * Rue is, alongside Niko and The Author, one of the only characters to remember the player even between runs.
 * She is also the only one aside from the Author to remember the player more clearly.
 * It is vaguely speculated that she and Cedric are robots, since if Niko talks to Proto before speaking to anyone else, Niko asks Proto what it's like being a robot, however Cedric and Rue also respond to Niko's question.
 * This speculation is supported by an unused spritesheet of Rue having a wind-up key attached to her, although this could also possibly be a bow.
 * This speculation is confirmed through special dialogue that playtesters of the game saw on their version of the game.
 * When you have to put Rue, Cedric and Proto in the portal near the end of the Solstice run, Rue is the only one who doesn't have the "NPC" tag on her spritesheet