If you're finishing up the game, or jumping in on Xbox Game Pass, you'll want to unlock the Unmakyr fast. It's a BFG rivaling mega gun you get for finding Slayer Gates opened with Slayer Keys. Inside are combat challenge that will earn you the Empyrean Keys that will release the Unmakyr in the Fortress. There are six Empyrean Keys in total that can only be found by completing some very tough combat arenas. You can collect them as you play through the game but it will probably be easier play through a bit to level up and then backtrack because some of the fights are tough and involve hordes of high level enemies. Your reward for all that work, though, is an incredibly powerful gun that can decimate even the toughest enemies in seconds. Here’s how to get the Doom Eternal Unmakyr by finding the six Empyrean Keys you need.
1. Exultia Slayer Key and Gate
The Slayer Gate on Exultia will be the first you encounter and has one of the easiest Slayer Keys to locate. Next to the gate will be a cave on the left, head in and use the platforms to get to the top. Turn back where you should see a yellow dash top up. Use that to reach the opening in ahead and you’ll see the key below to your left on a floating platform.
2. Cultist Base Slayer Key and Gate
The gate you find during the ‘Infiltrate the Cultist Base’ part of this level is actually one of the trickiest to get because the key is quite hard to reach, even though you can see it and the gate clearly. Once you got the cultist's key and reached the statue you have to topple to proceed don’t go over it - you won’t get back. Instead head to the right of the statue and look down where you’ll see a climbable wall you can drop down to. From there you’ll see some yellow swing bars you can use to dash jump to another two climbable walls. When you reach the end of the second one turn around to see another yellow swing bar you can use to reach the key.
3. Super Gore Nest Slayer key and Gate
This is one of the trickier keys to get simply because you have to complete most of the level, which involves finding the yellow, red and blue Gore Keys. While you can reach the Slayer Gate easily enough, the key is off limits until you have the blue key. You’ll basically have to play through the mission until you have the blue key and then head back to the opening hub area, use the blue key to access the blue energy lift in the large central flesh tower and jump to the large climbable wall. Follow the corridor around to find the Slayer key and you’ll be looking over the entrance to the gate. Jump down and go along the pipe to reach the gate.
4. Arc Complex Slayer Key and Gate
This is an easy to access challenge. As soon as you find the gate, turn around and look into the hall behind you. Jump and dash to the climbable wall on the right and then from there you can see and reach the key easily.
5. Mars Core Slayer Key and Gate
You’ll reach the Mars Slayer gate during the section of the 'Reach the Portal' part of the mission where you have to ‘Fire the Ion Catapult’ and ‘Get to the Escape Pod’. The key is visible behind a grill but there’s a trick to reaching it. To the left of the key is a window with ‘Operations’ written over it. Head in there to find a console you can interact with that will make a wall move and a small platform rise up. Use the platform to reach the breakable grate on the right (the one on the left will take you an album collectible), grab the key and try your luck with the gate.
6. Taras Nabad Slayer Key and Gate
The Slayer Gate you find during the mission to recover your crucible is easy enough to open, you just have to solve a water puzzle first. The key and gate are close together but you’ll need to get rid of some radioactive sludge. Head across from the Slayer Gate until you reach the water filled room with the block in it.
Grab the radiation suit and take a dive in to find a green punchable wall just below the surface. Smash it and the water level will drop. Jump in again and go through the door at the bottom where you will find a small chamber where you can climb out. From there you’ll see a green target you can shoot which will open the gate below it to reveal another punchable wall that will drop the water level again. When you go to leave you’ll find the block in front of the door. Punch it to move it and then climb up to reach the climbable wall on the opposite side. From here you’ll be able to see another green target to shoot to open the gate. Go through and head left, left again then right. You should see a chamber ahead, ignore it and turn left to follow the corridor, find the key and open the way back to the Slayer Challenge.
Unlocking the Unmaykr
Once you have all six Empyrean keys you can unlock the Unmaykr, the most powerful gun in the game. It’s like an LMG that fires a rapid spray of bullets in a flat arc. It shares ammo with the BFG and is just as lethal but more controllable, mincing even the largest enemy down to chunks in a matter of seconds. Combine it with the infinite ammo cheat and you can melt through levels in minutes.
It is pure filth.