Doom Eternal: Ancient Gods – All Codex, Rune Key & Secret Locations | The Blood Swamps

The Blood Swamps is the second completely insane level included in The Ancient Gods 1 expansion for Doom Eternal. This is a very different kind of hell, and it’s packed with some truly absurd challenges that will drive even the most hardcore players insane. There are new enemies here — constant Buff Totems, and Marauders around every corner.

And there are more collectibles to grab between hyper-active demon battles. We’ve got them all listed below for you to peruse at your own pace. The collectibles are easier to find this time around — if you check the map often, you’ll spot little areas you haven’t explored. There’s always something in those little corners. If you need confirmation, just check the locations (and screenshots) below.


More Ancient Gods DLC guides:

UAC Atlantica Facility Collectibles Guide | The Holt Collectibles Guide | How To Unlock Support Runes & Which To Pick First


In the Ancient Gods campaign, you’ll earn new skins for completing all of the Secret Encounters in a stage. You’ll also earn new Support Runes by completing the challenging Rune Gates.

Support Rune: Defeat the Marauder in small arena past the swamp and giant tentacle. Go to the ledge with the fire-traps, and at the end drop down. There’s a cracked wall leading to a secret path.

Codex #1: After jumping the gap over the Marauder arena, drop into the swamp below (past where you need to double-jump and double-dash) and land in the water where a Cyber-Mancubus spawns. Right beneath the water, there’s a hidden alcove with a codex.

Map: Emerge from the water past the Cyber-Mancubus to find the level map.

1-Up: Climb up from the map into the arena with the Baron of Hell. Defeat it, and smash the cracked wall in the left-corner.

1-Up: Taking the left path first, clear the first encounter and swing on the pole. You’ll need to jump to a raise ledge — there’s a lower ledge you can jump to hidden behind a thin waterfall that contains a 1-Up.

1-Up: In the left trial arena where the Doom Hunter appears, dive into the water pool and smash the cracked wall below.

Secret Encounter #1: The secret encounter on the left side of the level is found after leaving the foggy swamp arena with the Spirit. You’ll find it in a cage, in an upper room after several pole jumps.

  • To open the cage, continue until you reach the main trial chamber past the Tyrant encounter. After that, the demon wall will lower, giving you access to an optional path opposite the main door. Punch the box down off the ledge.

Codex #1: On the left side, you’ll reach a Tyrant arena with invisible Whiplash enemies. On the right edge, there’s a pool of water you can dive into. There’s a codex and some BFG ammo at the end.

BFG Ammo: After reaching the top of the obstacle course on the left trial, there’s a cracked door you can smash.

Codex #2: Past the obstacle course, you’ll reach spinning poles. Jump to the ledge where the Pain Elemental spawns and then jump to the far tower — from this small tower, you can reach the ledge with this codex.

Codex #3: On the right path, you’ll enter an area where you have to stay with the spirit dog for protection. Once you complete this section and unlock the trial chamber, go toward the swamp. There’s a pillar where you can leap onto a distant pole where you can connect to a climbable wall.

Secret Encounter #2: From the codex, drop into the deep hole on the upper walkway. It leads down to an optional path that will take you down and behind the Secret Encounter chamber.


More DOOM Eternal guides:

10 Tips & Tricks To Start Demon Slaying Strong | Beginner’s Guide | How To Unlock The Unmaykr | Secret DOOM 64 Gun Guide | Cheat Codes Collectibles List & Locations Guide | How To Farm Weapon Mastery Challenges | Best Runes To Unlock & Equip First | Easter Eggs Guide | Tie-In Novel Trash, Dopefish, Unmaker & More | How To Unlock Doom & Doom 2 Classic