Guild Wars 2 Halloween 2012 Mad Memoires XII: Descension

Site 10: “Walk in cadence with King Thorn's shattered subjects. They keep their hatred deep within.”
The Location of Wynn within the Shattered Keep above Fort Cadence

Head into the Sparkfly Fen by heading South through the Bloodtide Coast, if you have access to the Whisperwill Waypoint it is easy to use that to make it to the Fen. Head West from Braggi's Stead to the Fort Cadence Waypoint. Once there head to the North from the Waypoint into the Tomb there. Head down the steps and toward the back right of the area. Start using your scanner on #3, Etheric. This will trigger a suspicious location underneath a nearby torch. Interacting with that will trigger a conversation between Wynn and a villager. Talk with Wynn afterward to hear what he has to say:

Wynn: “It was as simple as killing a regular man. The king had powerful allies and magic of his own. He swore that he would return from the grave and make miserable his enemies. We all believed him.”
Hero: “So, what did you do?”
Wynn: “We murdered him from ambush, but didn't stop there. We put his pieces in different boxes so we could hide them with obscuring spells.”
Hero: “What did you do with the boxes?”
Wynn: “Each of us took a box to a secret location and buried it deep. If he couldn't piece himself back together, then he couldn't return.”
Hero: “Did it work?”
Wynn: “The spells that kept his body parts hidden are weakening under his strong magic and willpower. It has, after all, been five hundred years since we cast them.”
Hero: “Thanks. I'll make a record of your story.”

This will give you Mad Memoires XII: Descension, “In which Mad King Thorn is scattered to the four winds and departs for the Underworld.”