Ahghairon's dragonward

Ahghairon's dragonward was a powerful mythal cast by the famous mage Ahghairon over the city of Waterdeep.

Effects
Centered under Ahghairon's Tower, the mythal projected a permanent 12,800-ft-radius (3900 meters) dome, which encompassed the city as it existed in Ahghairon's day. The effect doesn't extend to the harbour or into Undermountain. In newer areas of Waterdeep, the dragonward's effects were less severe or non-existent.

Any creature with draconic blood that tried to enter the city was overcome with an overwhelming urge to leave the area, never to return. However, any draconic creature that touched the Dragonstaff of Ahghairon was able to bypass the dragonward for as long as the staff's wielder allowed or until the creature was struck by the staff.

History
In the mid-11th century DR, Ranressa Shiard returned as a hero from her journeys to Waterdeep atop the mighty copper dragon Galadaeros. Although she was welcomed home, the appearance of her mount flying over the city unsettled the majority of the populace. Ahghairon crafted this mythal to allay their fears.