Gwen

Description
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 give you the Gwen's Flute quest in which you need to find her lost flute. If you complete the quest she will want to follow you in your adventures. She is a very useful sidekick as she is never targeted by enemies and can heal you for 20 HP when your health is down.

After completing the quest, 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 also give gifts to Gwen. You may buy her a new flute and Small Girl's Cape from a merchant and you may give her Red Iris Flowers which she can't have enough of. 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. Also after buying her a new flute and the Small Girl's Cape her appearance will change to show the items given.

Dialogue
Gwen speaks of many things as she follows you around. All the characters she talks about are characters you meet in the game. The following are Gwens lines:

While following
 * "Prince Rurik and Lady Althea are going to get married! I can't wait! I hope I get to attend the wedding. I just love weddings!"
 * "Are you a hero, too, like Aidan and Devona? My daddy was a great Warrior, but he died when I was seven. Mommy says maybe we'll see him again after we die. Do you think that's true?"
 * "When I grow up, I'm going to be a hero like my daddy. I'd like to be a warrior, but the Mesmers' outfits are nicer, don't you think?"
 * "Have you met my mommy? Her name is Sarah. She's the town herbalist. She helps make sick people well again."
 * "Lady Althea's father is a duke. That means he's important, and he knows Prince Rurik. I'd love to meet the prince someday."
 * "Mary Malone brought us apples today. They're so lovely and ripe! Mommy wouldn't let me have one. She's saving them to bake a pie. Yummy!"
 * "Mommy says I shouldn't bother the grownups so much, but there aren't any children for me to play with. Besides, they're all so nice to me! Well, most of them are, anyway."
 * "Old Mack has a bull named Bill, and he's really mean. Once I saw him chase a man and hurt him real bad. Someone ought to do something about him. If my daddy was here, he'd kill that old bull and carve him into steaks!"
 * "Mr. & Mrs. Hathorn have children, but they're too young to play with me. Sometime Mrs. Hathorn lets me hold the baby. He's so cute!"
 * "Devona is so pretty! I love her hair. Do you think my hair will be that pretty when I grow up?"
 * "Are we there yet?"
 * "I'm on an adventure!"

While not following
 * The Red Iris Flowers are my favorite!
 * I wonder how many flowers it takes to fill a vase?
 * You look really strong. Can you teach me anything?
 * When I grow up I want to be just like you.
 * I want to be an adventurer too. Can I come with you?
 * My daddy was an adveturer like you. Once, he let me go on an adventure with him.
 * Eww! A big beetle!
 * Someone help me!
 * I think I'm going to follow you!

Post-Searing
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.