Unser Diem was a Mesan citizen and an employee of the Jessyk Combine.

In the late 1910s PD, he served as the Combine's official representative on Erewhon. He was also an associate of Haicheng Ringstorff. To obtain certain code information after the attempted kidnapping of Princess Ruth, Havenite secret agent Victor Cachat shot Diem in the shoulder, and he spilled everything he knew. (CS1)