friend Jaus' O.C., Isolde Brauer, an obersturmbannführer (lieutenant colonel) in the Sicherheitsdienst or SD, the SS' security service. They were the parent organization of the Einsatzgruppen, and generally the worst of the worst as far as truly hardcore Nazis went. They were also the ones primarily responsible for the oppression and elimination (i.e. murder) of "undesirables" (this task being performed first by the Einsatzgruppen's terror troops, the Einsatzkommando, and later the Totenkopf Division).
Isolde here is a rarity, a female SS officer. In general, the Nazis were very sexist in addition to being racist and homophobic, and so typically female Germans were not allowed to become officers.
However Jaus' idea is that Isolde started out as a radio operator before showing aptitude and gradually managing to rise through the ranks and become an obersturmbannführer, however, the disdain her male colleagues had for her ensured she was relegated to non-combat duties in the SD. Nevertheless, determined to prove herself useful to the Fatherland, Isolde throws herself fully into her duties, meaning she zealously commits a variety of war crimes and in general is just plain nasty. But her hardness and dedication to the Nazi cause earn the respect and loyalty of the men serving under her.