Kreigsmarine (English: War Marine) is naval part of the German Armed Forces. They have both naval fleets and marine troops at their disposal. Appears in Wolfenstein 2009, Wolfenstein: The New Order, and Wolfenstein II: The New Colossus.
In Wolfenstein 2009, they only appear in cutscene. Their battleship, Tirpitz, is infiltrated by B.J. Blazkowicz. They were transporting the Thule Medallion and on mission to missile launch for London. Operation was failed because the ship was sunk before the launch due to BJ's sabotage and the medallion has been stolen by him.
Wolfenstein: The New Order
In Wolfenstein new order they have more major role. Kriegsmarine now runs operation on Eva's Hammer, the colossal submarine. They now have blue color uniform soldiers and shrapnel armed Fire Trooper in game. Eva's hammer has nuclear stockpile and ability to launch it, so it was very statically important. BJ sneaked through the submarine and able to take control of it by killing most of the crew and the captain, Anton Krieger.
Wolfenstein II: The New Colossus
The some of forementioned crew was found to be alive in Wolfenstein 2. They were sending transmission on Ausmerzer in hopes to they find and rescue them in hidden area of the submarine called "Section F". Eventually they are eliminated by BJ.