Wilhelm Ballad first appeared in Trails in the Sky the 3rd, where he can be seen talking to Hermann Conrad on board of the Lusitania.[Note 1] He financially contributed to the luxurious passenger airship, but sold off his rights for several million mira right before the start of the Erebonian Civil War.
Assault on Ordis
Following Duke Croire's arrest as a result of the October War, Wilhelm intended to succeed him as the next Duke Cayenne, being the interim ruler of Ordis at the time of his arrest. Despite his position, Wilhelm was extremely arrogant and lazy, much to the chagrin of his fellow nobles. Wilhelm used his position to take public funds for his own enjoyment, and his incompetence also led to the capture of several railway guns by Ouroboros and the Northern Jaegers. When the society attacked on June 18 S.1206, Wilhelm immediately fled the city to take shelter in Juno Naval Fortress, leaving the evacuation efforts to Marquis Hyarms.  Unaware that the naval fortress would be occupied by Ouroboros and the remnants of the Northern Jaegers, Marquis Ballad is eventually confronted by Arianrhod and subsequently imprisoned by the Stahlritter.
Wilhelm is eventually saved by Class VII, upon which he attends the Provincial Council meeting later that night. Due to his incompetence, the council decides to elect his grandniece, Mildine Juzalith de Cayenne as the successor of the Cayenne Dukedom. Wilhelm is initially unaware of who Mildine is, until he realizes that he had met her as Musse earlier. As he is dragged away, he yells to the council that they are making a mistake.
Stripped of his ambitions, Wilhelm is sent to Saint-Arkh as a government official, signing numerous papers as part of his duties. Woefully bored of his job, he attempted to find some entertainment to no avail, as the town lacked a casino and a club. He is first encountered by Class VII as they arrive to search for Alfin Reise Arnor and Tita Russell, where he attempted to leave the estate, only to be dragged back in by the Imperial Defense Force.
Wilhelm then decided to look for musicians and dancers to entertain him, but he was left unsatisfied with their performances. After hearing of the "Black Rabbit and Redheads", Wilhelm had his personal guards sneak them into the estate. Much to his surprise, he discovered that they were Class VII, and was unsure of what they had come to question him for. Upon hearing that they were looking for Alfin and Tita, Wilhelm informed them that they were supposed to arrive at the estate, but were diverted to Dreknor Fortress. He then had his personal guard sneak Class VII out of the estate to avoid making matters worse.
Following the Great War, Wilhelm was made the acting ruler of Lamarre Province as a result of the government and Musse's actions. The additional workload proved to be too much for him, who sought more ways to keep himself entertained and wished to connect with the younger generation. He acquired the Bobcat in a deal with Josette Capua. In the process, he ends up getting investigated by Machias Regnitz under the pretense of using government money for personal gain, only to be proven innocent when Machias finds out that Wilhelm had bought everything with his own money. He then tries to destress himself by using the airship, but it suffers minor damage as a result of a turbulence problem; regardless, it was enough to cause him to ditch the Bobcat outside the Epstein Foundation's headquarters.