He earned his title of Sergei the Apprehender as a top-notch investigator with the Crossbell Police Department, where he also supervised Guy Bannings and Arios MacLaine. Under his lead, the First Division's accomplishments exceeded far of what was expected of them.
Special Support Section
After he left the First Division, Sergei became a driving instructor at the Crossbell Police Academy until the establishment of the Special Support Section at the beginning of S.1204. As the acting Section Chief of the SSS, Sergei directed the group to hot-button issues in Crossbell that they needed to resolve and acted as their representative in the Crossbell Police Department. Sergei stressed that the SSS needed to come to decisions independently and to rely on their own judgment as a group in order to make sound decisions in the field and to take quick, effective action.
If the situations calls for it, Sergei quickly dismisses his laid back attitude and immediately takes the initiative. When Joachim Guenter manipulated the Crossbell Guardian Force into attacking Crossbell using Gnosis, Sergei readied his shotgun to hold off the brainwashed forces so that the SSS could escape together with KeA.
After aiding the SSS in their escape, Sergei offered to drive the group to the Sun Fort at the Ancient Battlefield where Joachim was waiting. While attempting to evade the hail of gunfire firing towards the car, he told the SSS that he considered it his duty to clear the path for youngsters like them.
During the Imperial occupation of Crossbell, Sergei collaborated with the resistance in the form of transporting relief supplies.