Gwen

Gwen is one of the bigger mysteries in the game. She is a little girl that you encounter in Lakeside County just oustide Ascalon City. In the beginning she will ask you to find her flute in the Gwen's Flute quest. If you complete this quest she will want to follow you in your adventures. She is not a bad sidekick as she is never targeted by enemies and can heal you for 20 HP when your health is down.

From that point on, whenever you exit a town in Pre-Searing Ascalon you will find her standing there, waiting for you. Speak to her to have her follow you and speak to her again to have her wait.

You may give Gwen gifts in Pre-Searing Ascalon. You may buy her another flute, you may give her Red Iris Flowers which she cannot have enough of, and you may give her the Small Girl's Cape (which you can purchase at any merchant). After giving her these gifts (all or some of them), she will give you the most valuable thing she has (according to her) which is the Tapestry Shred.

Gwen speaks of many things as she follows you around. All the characters she talks about are characters you meet in the game. Here are the things she likes to talk about:
 * Prince Rurik marrying Lady Althea and how she hopes to attend the wedding.
 * Devona's hair.
 * Her father was a warrior like Devona who died when she was seven.
 * Being a hero like Devona and Aidan.
 * Adventuring!
 * Her mother Sarah being a healer.
 * Duke Barradin being a duke.
 * Mary Malone giving some apples to her mother.
 * Her mother saying she should not bother grown-ups so much.
 * Old Mack's bull scaring her.
 * Mr & Mrs Hathorn having a few small children that are too young for her to play with.

After the Searing you will be able to find a Tattered Girl's Cape and Gwen's Broken Flute as remnants of Gwen. Her fate, though, is unknown.

It is believed by many players in the game that, given the availability of Gwen items at every merchant before the Searing and given that her items are marked as Quest Items, that there is some quest that has to deal with her fate after the Searing that is yet to be announced.

Upon entering the Underworld via the Temple of the Ages, players will see the ghost of Gwen's mother, Sarah, worriedly asking other ghosts if they have seen her daughter.

Trivia
At the end of one of the BWEs during the beta stage of the game, the developers at ArenaNet unleashed a destructive Gwen upon the unwary citizens of Tyria as seen in this screen capture and in this movie (must be logged in to view).

This fueled the famous wallpaper (by a player) that shows her as some creepy demon-possessed child. Some players have misconstrued this as Gwen's actual future role.