Sir Wilhelm von Algenburg is a knight from a minor noble family in the northern Kaselreich, in Pomerija. He was drawn, as many were, from the converted Pagan peoples of the regions seized by the Kasonic Order. He himself never knew infidel ways, and was raised a proper Genosian.
Wilhelm pursued an education, and became an errant knight, chronicling events in distant lands to bring back and fill the libraries of his homeland. He has been to the Slivers, to the far north, to Sacred Ruvia in the South, to Helion, the flying city at the heart of the broken sea.
On a trip to the East, Wilhelm would meet a young Sarah Gizka on the Steppe, and the two briefly worked together in acquiring a gemstone of great significance (historical, to Wilhelm, monetary, to Gizka) for the Order of the Black Sun in the Reich.
During this mission, several members of the company, including Wilhelm, were trapped inside a pagan temple deep in the steppe for several weeks in a... Sort of Rorke's Drift scenario, besieged by thousands of natives with a very small force. During this time, Wilhelm became very impressed with Gizka for her indefatigable nature and for keeping her men (and him) alive for this long.
When the time came to make their escape, Wilhelm sacrificed himself by tackling a Marju off of a bridge into a riverbed to save Gizka's life. She never knew of his sacrifice, and escaped with her men.
Wilhelm was taken prisoner, and tortured and enslaved for eight years by the Marju, before being found by a Karthacki punitive expedition into the steppe, which slew his captors and captured him.
No one is entirely sure what happened to Wilhelm von Algenburg in Kar-Ischil, but he returned to Western Vosca sometime later, a changed man. No longer the gregarious scholar he was in youth, but a fearless, silent warrior in a helmet he rarely removes, and who carries himself with an imposing martial swagger. He is often seen in the company of a Karthacki priestess, whom he accompanies through the Genosian lands for unknown reasons.
Though in the prime of his youth as a warrior and a knight he was no famous killer, known better for his poetry and his margin illustrations than for his jousting and performance in the melee, Wilhelm has recently killed several famous men in battle, including two knights of significant renown.
Once he was known as Wilhelm the Reader. Now he is called Wilhelm the Strong. Nobody knows what brought on this transformation in character.