- "Now is the time of our judgement! The whole of the Empire looks upon us this day, and should we fail there will be no history to record our defeat. This is where we make our stand and prove the worth of the men of the Empire. Fight to the death and fight for Sigmar!"
- —Stefan von Kessel, addressing his troops during the Siege of Talabheim.
Once the heir apparent to the League of Ostermark, ever since he was a young boy, Stefan believed that his grandfather and father were worshippers of Chaos. Branded across the face as an infant with the Mark of Chaos, he bore the scars of this suspicion physically as well as mentally.
His family stripped of their titles and wealth, Stefan made a life for himself in the Empire's army. He was determined to prove his loyalty to the Empire, and had a fiery dedication to Sigmar. He loathed Chaos in all of its guises and was vehement that the Empire would be victorious against the warbands invading from the North. He was an educated man, and a veteran of the Great War Against Chaos, with a confidence and tone of command honed on bloody battlefields across the Empire...
Mark of Chaos
During the course of his campaign to cleanse the lands of Talabecland, Ostland and Ostermark, Stefan won many great victories. Allying with the Elven host of Aurelion and Prince Khalanos, he not only fought against the rampaging hordes of Chaos, but also the Skaven and Greenskin tribes that had begun to infest the Empire.
Eventually, after rescuing the Warrior Priest Gunther, Stefan uncovered a vile conspiracy. The holy man revealed that the current Elector Count of Ostermark, Otto von Gruber, was himself a Chaos Cultist and, to further compound his treachery, had been responsible for falsely accusing Stefan's father and grandfather of heresy, allowing him to take his family's land and titles away.
Enraged, the young Captain swore vengeance, but Gruber had risen high in Nurgle's favour. Gunthar explained that he could not be killed by any common blade. Indeed, Stefan would have to reclaim a potent relic that had belonged to a long-dead champion of Mandred Skavenslayer. The warrior had been slain in battle by a dreaded Vampire, with the sword taken as a trophy.
Thus, Stefan and Gunthar would go on to fight against the Undead hordes of Waldakir Rahtep. Delving into the dark caverns of the vampire's sanctum, the pair eventually came face to face with the Necrarch himself. Destroying the enchanted sarcophagi that fuelled the creature's power, they were able to overcome their foe, slaying him and reclaiming the ancient blade.
Now properly equipped for the fight ahead, Stefan and his forces tracked Gruber down to his dark fortress. At first, the traitor was protected from invasion by a vast miasma of pestilence, a sea of disease that killed many of Stefan's scouts. However, Aurelion and her Elves were able to destroy the Chaos shrine that powered the fortress's defence, allowing Stefan and his army to besiege it. In the end, Otto von Gruber, once an Elector Count of the Empire, was laid low by the son of those he had betrayed. As Gruber's corpse was reduced to a puddle of filth, Stefan reclaimed his ancestral Runefang, seeking to put it into good use once more.
Siege of Talabheim
Though the evil of Otto von Gruber had been uncovered and destroyed, a greater threat yet remained. Unaided by the Empire, the Elven host of Prince Khalanos had failed in their quest to halt the forces of Chaos in the north. Led by Thorgar the Blooded One, a Daemon Prince filled with unholy power, the Northmen and their allies invaded in huge numbers, intent on the walled city of Talabheim. The Elector of the region, Count Feuerbach, had been slain in single combat by Thorgar, and much of his army had been decimated during the Great War. Thus, Stefan and the Elf Mage Aurelion took command over the defence of the city, bringing with them the armies of Ostermark and Saphery.
At the height of the battle, Stefan, mounted atop a noble Griffon, engaged Thorgar in an epic duel. Eventually, the Daemon Prince was able to cast down the young Elector's mount, even as the warrior's Runefang pierced his unholy flesh. However, as Thorgar prepared to kill Stefan, he was suddenly engulfed in a blast of magical flame. Aurelion could not harm the Daemon Prince, but she was able to distract him. With his attention turned towards the Elf, the cannon batteries of Talabheim unleashed a payload of destruction upon Thorgar, banishing him to the Realm of Chaos. With their leader destroyed, the Northmen hordes soon broke and fled. Talabheim was saved...
After this victory, Stefan would go on to face the enemies of the Empire many times in his life. He became known as a fair and honourable leader, and he always led his army from the front. He fathered just one heir, and his bloodline runs strong in the noble house of Ostermark.
- As the Elector Count of Ostermark, Stefan had the right to wield the Runefang known as Troll Cleaver.