The fifth child of the Margaster Family, Brunyund became a formidable arcane warrior who made a pact with a fiendish entity to further his power. Despite his corruption, he cared deeply for his brother Willow and even aided the Seekers during their stay in Waterdeep, attempting to dissuade them from their mission against his family.
However, when the Black Talon assaulted the tavern where the group stayed, Brunyund betrayed Willow and was slain for it. His death served as the third sacrifice required to summon the Four Kings.