Nagel was an acolyte of Gellert Grindelwald in the 1920s.
Prior to 1927 Nagel joined Gellert Grindelwald and became one of his six trusted acolytes. He assisted Grindelwald in securing a home in Paris along with the other acolytes and helps dispose of the bodies of the former inhabitants. Nagel was sent to the Circus Arcanus to observe the performances and report on the activities of the Obscurial Credence Barebone. [CG]
"nagel" means "nail" in German, Swedish, and Norwegian