Grave Machine is the first map of the Realm of Cultists in Dimension of the Machine. It takes place in a large cathedral, as well as the catacombs beneath it.
- From the castle with the locked passage, head out the door to your right. Clear your way through all the enemies and you will find yourself inside some sort of mausoleum. At the intersection, go straight, then take a left; when you see the outside again, look to your left before exiting; the tomb on the left is cracked and can be shot/hit open to reveal a dead Ranger, two small Boxes of Rockets and a Pentagram of Protection.
- After falling through the floor all the way to the bottom of the castle, you will come to a corridor with enemies, then a small and dark room that leads to a second corridor. Enter this second corridor and immediately turn around; there is a Shootable Button high up on the wall, to the left of the doors you came through, which opens a secret wall just across from it containing a Yellow Armor.
- Immediately after the corridor containing Secret #2, you will come to a fork in the road, where you must initially go left and right, as the doors in front of you are locked. Head into the room on your right, which is a downward staircase with a Knight, a Death Knight and a button at the bottom. There is also a pool of water down here; dive under it for two small Boxes of Nails and a Red Armor.