Members of this family include Aaronev Wilhelm Sturmvoraus, Tarvek Sturmvoraus, and Anevka Sturmvoraus. Since the recent troubles in Sturmhalten, the only known survivor is Tarvek (although Anevka's head may just be in need of a body).
The status of the Storm King in the popular imagination and Tarvek's alliance with Agatha and Gil notwithstanding, the self-serving actions of most of this house's members (at least in the present narrative) and its role in the Storm King Conspiracy place it firmly in the "Villains" category, Tarvek excepted.
With Aaronev and Anevka now dead, Prince Tarvek is the titular head of the family. But few of the family's minions support him. His cousins, at least those still alive, are supporting Martellus von Blitzengaard in his claim to the throne of the Storm King, and the Smoke Knights are mostly taking orders from Grandmother.
The spelling of the family name varied between Sturmvarous and Sturmvoraus in the canon. Although it seems to have standardized and largely been corrected to the latter spelling, some remnants remain.
Possibly relevant outside information
"Sturm voraus!" means "Storm ahead!" in German ("storm" is a noun, not an imperative verb).