Doktor was originally a scientist specializing in the research of walking weapons from what was then Communist-occupied East Germany, and often pursued several methods of science. As such, he spent so much time working that he occasionally slept at his desk. One of his accomplishments during this time was creating magnetostrictive actuators, which changed shape relating to magnetics, an accomplishment that later gave him great shame when he learned that they were utilized on the Grad Unmanned Gears.
However, after the Berlin Wall fell, he was left without a job as his facility was shut down. His theories on myoelectric prosthetics were also the only reason he wasn't left as a homeless vagrant, as he often claimed. Eventually, deciding to put his knowledge of robotics and engineering to good use, he got a prosthetics laboratory at Dortmund to hire him. His knowledge on the subject revolutionized the concept of prosthetics, and he eventually found himself the head of his own lab. Eventually, he got contracts from PMCs to aid in prosthetic-related surgeries.
He also collected cyborg left arms, feeling it was his duty to expand and improve upon cyborg development by using the arms to create a database. By the time of 2018, he managed to collect at least 56 left arms, which he placed onto a shelf at his lab that allowed for fourteen arms per shelf. He also trained Raiden in two VR missions.
Doktor was eventually called in by Maverick in 2018 to aid in supplying Raiden with a new body, as their original surgeon had gone into hiding for unknown reasons. He was initially bewildered, as he had not done a full-on body reconstruction before, although his surgery on Raiden resulted in him mastering the concept of both partial and full-body cyborgification. He also modified a VR simulator prior to Raiden's redeployment in order for him to train and grow accustomed to his new cyborg body.
Doktor is a very skilled pilot and had an interest in learning from scientific colleagues, expressing a desire to meet Sunny and Hal Emmerich. One of his few problems is the fact that he can turn a short conversation into a really long lecture about the technology he's built or researched. He speaks with a heavy German accent that occasionally slips into his native tongue.
His personality is that of a joking manner. He tends to crack a joke or two every so often, even on missions.