As you play through the Campaign, you collect Enigma Codes from defeated Kommandants. Once Grace unlocks the Enigma Machine, you can use those codes to find the locations of Überkommandants—the elite Nazi leaders.
When using the Enigma Machine, select the Überkommandant you want to find. Each Überkommandant’s location carries an associated cost in codes you must pay. Some cost more than others. Once you pay, you must complete a timed minigame in which you move top and bottom code wheels to match the code. If you fail, you start over and must pay more codes for another attempt. A successful attempt unlocks the location for that Überkommandant.
After you’ve found your target location, head to the war map in the middle of the helm. Select the location and then the unlocked district within that location. This sends you into the mission to assassinate the corresponding Überkommandant. These missions take place in the same areas as the Campaign missions. However, new areas are often accessible that couldn’t be explored in the Campaign. As you advance toward your objective, keep an eye out for additional Collectibles that can only be found during these missions.