They may be outdated, but they're all we have until they get the book out... eventually.
I'm starting to tire of having to pull up the HTML copy I made while Kaja still had them up, so here for everybody's easier reference is the text of the entry on:
Wulfenbach was originally a minor house in Eastern Europe. Klaus’ parents were both Gifted scientists who ran their small holdings well, used their talents for the good of their people and for the most part kept out of the politics so common amongst the Gifted. This couple is said to have had three sons, all Sparks of varying degrees who worked in the lab alongside their parents. Klaus is the only one that anyone has seen in years. Rumors abound as to the fate of the other two, but there is no one who knows for sure.
Klaus is one of the most powerful of the Gifted in known history. The Sparks tend to be specialists. They produce giant insects, or flying warships, or surgically enhanced super-soldiers. Klaus’ genius lies in his ability to absorb and integrate the work of others, and usually improve upon it. His primary interest, however, has always been the nature of the Spark itself.
Klaus spent much of his early adulthood adventuring with the Heterodyne Boys. He believed that their unique idealism could solve the problems that fueled the Long War. The friendship changed with the addition of Lucrezia Mongfish, the daughter of a truly evil mad scientist that the group went up against on several of their expeditions. Although she had initially been helping her father in his plans, Lucrezia was eventually convinced of the error of her ways and joined the group of heroes. A tense love triangle developed that ended with Lucrezia’s marriage to Bill Heterodyne and Klaus’ disappearance. It was generally assumed that he, as the defeated rival, withdrew for a time to forget the girl who rejected him.
Klaus was not heard from at all during the years when the Other was active. Many people whisper that Klaus himself was the Other and the devastating attacks were a hideous revenge directed at the Heterodynes. Klaus returned only after the Other’s attacks had ceased, and he returned in a very bad mood. His early idealism had vanished and his new strategy was simple. He drew a circle on the map and declared everything within it his territory. Every year the circle grew. Aside from a few basic rules, things were to stay the same. The ruling Sparks would stay in power, but no hostilities whatsoever were allowed. Any breach of this Peace was met with ruthless conquest and the swift removal of the aggressors. At first no one took this very seriously, and many of the Gifted rose to challenge Klaus. He wound up in control of much of Europe in just a few years.
Even though he stopped the fighting, Klaus is not popular. The surviving Great Houses want their power back, and the common people believe him to be responsible for the ruin of the Heterodynes. In stories, folksongs and plays, Klaus is usually portrayed as a traitor, always as a villain. Few people bother to point out that it speaks well for his rule that no retaliation is ever made for such amusements.
Even though they dislike and fear him, the people know that the Baron’s Peace will most likely only last as long as Klaus himself. On account of this, there are many wishes for his continued good health—at least until the Heterodynes return.
Copyright and all rights reserved, Studio Foglio - reproduced w/o permission but with the best intentions in mind
It's got some fairly cut-and-dried answers to 'why is he hated' and 'where does he come from' that have been, IM cranky O, rather pointlessly debated in Some Places, of recent memory.
In lighter tone, a photograph of the Baron doing what he can to ensure that Truth Will Out: