You want to collect as much as possible in Doom: Eternal to unlock all secrets and find all hidden goodies developer software placed out of the way. Plenty of them are on the map for you at all levels, making them easy to spot, even on Fortress of Doom, your hub ship. One important secret that many players will want to go out of their way to acquire are the Empyrean Keys. You use these keys to get the final hidden weapon in the game.
To receive these Empyrean Keys, you must complete the Slayer Gates found throughout the Doom: Eternal levels. Slayer Gates are among the toughest challenges in the game where players battle a mighty wave of demons, with a handful of mini-bosses in there for good measure. You can complete them on any difficulty, and it will count towards unlocking the weapon. You can find six of them in the game. They are at these levels:
- Exultia
- Cultist Base
- Super Gore Nest
- Arc complex
- Mars Core
- Taras nabad
You can complete them on your first part of the game, or you can choose to repeat the game to continue them. If you revisit the missions through Mission Select, you need to make sure that the cheat codes are not activated. Cheat codes are one of the secrets you can acquire in the game, and you can activate them when you repeat a mission through Mission Select. However, you will not be able to access the Killers' Gate when the Secret Codes are activated. Developer id Software wanted to make sure players completed them naturally, without the aid of cheat codes that provided ammo or endless lives.
For those looking for the Empyrean Keys, recheck any of the above missions to see which of the Slayer Gates you haven't completed. Once you have all of the Empyrean Keys, you can bring them to the Fortress of Doom to unlock the weapon.
