Common knowledge around "Winterhaven ":http://www.obsidianportal.com/campaign/ekria_unearthed/wikis/winterhavenis that the Keep on the Shadowfell (More commonly referred to as Shadowfell Keep) was once a site of great evil magic, that was stopped by a group of powerful adventurers, hundreds of years ago.
Now, it is thought to be a site for brigands and monsters to hide from the rest of the world, rarely venturing out to raid villages or attack merchants. Nobody really knows what’s going on there, but there’s no doubt that people are up to no good.
Only recently, the group of "Maelstraen ":http://www.obsidianportal.com/campaign/ekria_unearthed/wikis/maelstraensurvivors found compelling information linking the "Maelstraen ":http://www.obsidianportal.com/campaign/ekria_unearthed/wikis/maelstraenattack to a man named Kalarel, who’s own soldiers have said is based in the keep.
The information that the group has gathered indicates that "Kalarel ":http://www.obsidianportal.com/campaigns/ekria_unearthed/characters/kalarelis attempting to open some kind of ‘Rift’, which according to "Valthrun ":http://www.obsidianportal.com/campaigns/ekria_unearthed/characters/valthruntheprescientwill allow legions of undead soldiers to pour through the rift into the world.
Rumor or not, there is something going on at Shadowfell Keep, and the attack on "Maelstraen ":http://www.obsidianportal.com/campaign/ekria_unearthed/wikis/maelstraenis involved.