You can change the appearance of your doom guy in DOOM: Eternal to change his appearance during your campaign and your cutscenes. To access several of them, you must unlock specific locations of your main vessel, the Doom fortress. One of the notable armor that you can unlock on this ship is the appearance of Sentinel armor.
To find this armor, you must start on the first floor of your ship, where you initially load the game. From there, go left and go down the stairs to the second floor. Go around the area and continue left through the two -door series with slow opening. At the other end of the last door, you should see a broken path you can jump and go to the other side. Sentinel armor is available there.
If you want to have access to this armor, you need to use two of your sentinel batteries to acquire it. You can get them in any mission of the game or by completing the three challenges of any mission. You can use cheat codes to facilitate your trip to the mission selection screen. After acquiring these two batteries, return to this entry to unlock the armor. If you want to wear it, you must go to the main menu of your game and go to the customization options to modify the appearance of your Slayer.
There are various secrets and hidden meetings dispersed everywhere DOOM: Eternal. Make sure to find them and also unlock the customization options for Classic Marine and Preator armor also available on the Fortress of Doom.