Shadowfang Keep

Shadowfang Keep is a haunted keep in southern Silverpine Forest, near Pyrewood Village. It is the base of operations for the evil archmage Arugal and his worgen progeny.

History
The courtyard

From Blizzard's Official World Dungeons site:
 * During the Third War, the wizards of the Kirin Tor battled against the undead armies of the Scourge. When the wizards of Dalarandied in battle, they would rise soon after - adding their former might to the growing Scourge. Frustrated by their lack of progress (and against the advice of his peers) the Archmage, Arugal elected to summon extra-dimensional entities to bolster Dalaran's diminishing ranks. Arugal's summoning brought the ravenous worgen into the world of Azeroth. The feral wolf-men slaughtered not only the Scourge, but quickly turned on the wizards themselves. The worgen sieged the keep of the noble, Baron Silverlaine. Situated above the tiny hamlet of Pyrewood, the keep quickly fell into shadow and ruin. Driven mad with guilt, Arugal adopted the worgen as his children and retreated to the newly dubbed 'Shadowfang Keep'. It's said he still resides there, protected by his massive pet, Fenrus - and haunted by the vengeful ghost of Baron Silverlaine.

Pyrewood Village is shadowed to the north by Shadowfang Keep, once a bastion of Alliance power but now the dark residence of a mad former mage of the Kirin Tor, named Arugal. The worgen that stalk the Keep, as well as the cursed villagers of Pyrewood, are the doings of this madman. During the Third War, Arugal made these worgen as allies but they could not be controlled and turned on him and the other soldiers. He went mad after this and now accepts them as his "children." His worgen run rampant throughout much of the forest.

During the events of World of Warcraft, agents of the Banshee Queen Sylvanas Windrunner were dispatched to both solve the mystery of the enigmatic worgen and ultimately terminate the source of the creatures' infestation in Silverpine. Eventually they were able to discover that the mad archmage, Arugal, was behind the worgen's presence, and the Forsaken command ordered him slain.