Von Geiz was a male who held the position of Chief Medic within the ranks of the 61st Mobile Infantry. In the chain of command, he was the fourth in line, following Captain Micha Evon, Lieutenant Sairgon, and Commander [Paonu]. His responsibilities encompassed all aspects of medical care for the 61st, and he was responsible for approving soldiers' return to duty after recovery. Throughout the Galactic Civil War, he served with the 61st in major engagements, including the Attack on Haidoral Prime, where they rescued the defecting Governor Everi Chalis, and the Siege of Inyusu Tor, where the company faced near-total destruction against overwhelming Imperial forces. After the death of Captain Evon, Von Geiz assumed a more prominent leadership position in Twilight Company. He gave his support to Chalis' proposal for Operation Ringbreaker, a campaign targeting the shipyards of Kuat.
Von Geiz possessed qualities such as kindness, intelligence, thoughtfulness, care, gentleness, and sympathy. First Sergeant Hazram Namir regarded him as one of the most gentle individuals he had ever encountered. He was someone Captain Evon trusted. As the Chief Medic, Von Geiz was proficient in various medical treatments and maintained a connection with every soldier in the company. During Twilight Company's traditional funeral rites, he would help locate individuals to speak in honor of the fallen soldiers.
Von Geiz made an appearance in the 2015 novel titled Battlefront: Twilight Company, which was authored by Alexander Freed.