When the developers ignore bugs, the community does not. This is a patch for the Dawnguard DLC, fixing hundreds of bugs left over by Bethesda. Now that game-breaking bug won't prevent you from completing the quest. Note that this is the last version of the standalone patch. Current versions use the "Legendary" patch, which is available here on GameWatcher.
Adds a Small Quest to defeat a necromancer, who has acquired two powerful necromantic artifacts: The Bloodworm Helm, and The Staff of Worms. To start the quest, travel to the outskirts of Dawnstar, there you will find a Vigilant of Stendarr who has been attacked by undead.
