In the land of the Norse, few thing existed that could send a shiver up the spine of these hardy people. One such thing however, was the dreaded, Draugr. In the lore of the sagas, the Draugr was an undead warrior, with the desire to attack those that trespass aginst its barrow, and the ability to convert those who survive the attack, into a Druagr as well. In this fashion, they are quite similar to the current depiction of zombies in our current culture, spreading their curse. Unlike a zombie however, the Draugr possesses a semblance of human intelligence, as well as enormous strength, and a penchant for mystical abilities. These abilities could manifest themselves as shape-changing, control of the weather, and a loose aptitude for the telling of the future.
Mostly content to spend eternity in their barrow/ burial mound, guarding their wealth, the Draugr would sometimes venture into the outside world, wreaking havoc and instilling fear along the way. Some families, in order to confuse a dead loved-one who might return as a Draugr, would have a special door built into their homes, and then have it bricked up so the ghoul could not find its way in. This desire to return home was made manifest by an innate jealousy of what the living still possessed and to 'protect' that which the Draugr might still believe had belonged to them...their property. It became the custom for travelers at night to tap three times on the window or door of a hall/ home. Anything less would not be answered as the person on the otherside would be too frightened of the possible undead to respond. And if you did open your hall to the wrong 'individual'....you might be torn limb from limb, or disappear altogether as stated in the Flommana and Grettir's sagas.
As the Draugr was the bearer of supernatural strength, it was impossible for an ordinary hero to end its existence. The fact that an ordinary sword was unable to harm it as well, was another complicating matter. No, the only way to destroy a Draugr that was terrorizing a community, was to be a hero of mythic quality. One that had the ability to wrestle the Draugr to the ground. One that had the ability to travel to its barrow, retrieve a sword from within, and use it to decapitate the monster, thus completing only the first two stages of what at times, could be a complex ritual of destruction. Only then would the neighboring countryside be safe....at least until the next Draugr was disturbed.