Baron Klaus von Wulfenbach is a character in the Girl Genius comic book written and drawn by Phil Foglio and Kaja Foglio.

He is a "Spark," or mad scientist, with a particular interest in the workings, origins and nature of the "Spark,"---an inborn quality which makes some people able to intuitively make huge advances in the sciences, all too frequently conjoined with megalomania and a lack of common sense. He is also, as of the beginning of the current Girl Genius series, the uncontested ruler of much of Europe, having battled down many quarrelling Sparks and imposed order.

He has many people in his employ, ranging from "constructs" (artificial people, something like Frankenstein's monster), "clanks" (robots), and many people, including Bangladesh Dupree, a former pirate queen, and the children of many local rulers. His headquarters is a huge dirigible-like airship called the Castle Wulfenbach, which gives him the advantages of security, privacy and mobility.

While he is considered a ruthless tyrant, his motives are more complex than simple tyranny. In his youth, he adventured with Bill and Barry Heterodyne, the father and uncle of Agatha Clay Heterodyne, the heroine of Girl Genius, and shared their goals of putting down evildoers. After their disappearance, and an absence of several years, he came back with a son (his wife has not been seen for many years) to find things worse than ever, with Sparks fighting among themselves and chaos everywhere. Utilizing his own resources, as well as those of the Heterodynes and the Sparks he defeated, he put down the fighting and restored order. He dislikes ruling, much preferring to adventure or research, but recognizes that he is needed in his current role. His subjects do not note the discrepancy between their perception of him and his actual actions---among other things, he does not do anything to prevent himself being portrayed as a ruthless villain in popular entertainment.