How was the Norse mythological creature 'Fenrir' used or misused by the Nazis in WWII?

Hi
How was the Norse mythological creature ‘Fenrir’ used or misused by the Nazis in WWII? I haven’t been able to find any direct usage of Fenrir as such. The wolf’s head is a common symbol. but the doomsday wolf as a Nazi symbol? Did the Einsatzgruppen or Totenkopf organisation use any symbols representing Fenrir? I look forward to your feedback.