Wilhelm is an older, portly man with turquoise eyes, remnants of white hair and a thick moustache. He dresses extravagantly, wearing a gilded navy blue long coat with ruffles, gold chains and a purple feather lined collar and a similarly ornate violet waistcoat over a black ruffled shirt and white cravat which is pinned with a blue gemstone brooch. Wilhelm also wears dove gray pinstripe trousers and black shoes with a gold clasp.
Lazy and arrogant, Wilhelm is a hedonist at heart, shirking workload and responsibilities wherever possible to engage in a life of pleasure and entertainment. Despite his reputation for extravagant spending, Wilhelm seems to have a conscience and sense of morality, using only his own funds and providing assistance if it doesn't inconvenience him too much.
Wilhelm 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.
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.
He later conducts discussions with Lucy Seiland and Fernand Hyarms regarding the principality of Remiferia and their response to the Great Twilight. Right before the start of the Great War, Marquis Ballad is among the people who prepares to watch the war thanks to a link from Jona Sacred alongside Fernand and Celestin.
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[Note 2]. His life is saved when the crashing airship is supported and allowed to land safely by Tita Russell who was testing the Orbal Gear IV nearby. Regardless, it was enough to cause him to abandon the Bobcat outside the Epstein Foundation's headquarters.
Marquis Ballard is is enlisted to help judge the food for the Imperial wedding, which he does begrudgingly, stating that he shouldn't have to taste food made by commoners. Nicholas is said to have reached out o many people to help with the process, but it is implied Musse was involved in getting her uncle to assist. Despite his initial reservations, Wilhelm proves to be extremely knowledgable about the subtleties of each dish and begins to appreciate the efforts of each hopeful candidate. Ultimately, Ballard enjoys every single dish and ends up being the most respectful, chiding the others for not appreciating each of their merits, particularly Roselia Millstein who he quickly develops an antagonistic relationship with. He comes to be blown away by Freddy's dish, and gives it the highest praise despite its initial appearance.
- Kevin Graham remarks that one of the persons talking to Hermann Conrad looks like "Marquis Ballad, known for his extravagant spending".
- The presence of the cloaked Emperor nearby implies he uses his gravity abilities to bring down the aircraft, in hopes of using the situation to get hold of Tita's artefact, which may have been the missing Monarch's Regalia- the Orb. The orb had been missing when Emperor confronted Nadia Rayne and Swin Abel for the last time, and later turned up in the Black workshop from where Schmidt and Tita obtained it later.