Bludtharst Heterodyne

Bludtharst Heterodyne is one of Agatha's ancestors, active roughly 200 years before the start of the comic. Along with his father Clemethious, he mounted one of the family's more aggressive and widespread assaults on Europan civilization, an effort which was bloodily opposed by the Storm King Andronicus Valois. His sibling was a rare Heterodyne female, Euphrosynia.

He is at least in Portentius Reichenbach's opera The Storm King, although it appears that the main villain of the piece is Euphrosynia's villainous fiance Ogglespoon.

to the Castle Heterodyne fragment/mini-clank Agatha acquires in Paris, Bludtharst managed to corrupt the powers of Andronicus's mace The Platonic Solid; it is not yet clear if this corruption is what led to the Storm King's transformation into a glowing undead berserker.