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The Sentinel Command Station is under attack in Chapter 12 of Doom: The Dark Ages. This flying techno-base is a complicated web of rooms that require multiple keycards to access. Here we’ll show you how to get every key, where to find every locked door, and how to complete your collectibles collection. There’s a lot of secrets in a very tight space, so here’s where to find everything.
Challenges | Chapter 12
- Punching Bag: Strike a Battleknight with a melee attack 10 times.
Battleknights are the big melee-only demons that charge straight for you wearing heavy armor. Use melee attacks against them — try parrying their melee attack, then go for a three-hit combo with the flail. Repeat a few times to complete this challenge. This works even if they’re still wearing full armor.
- Wait For It: Kill 10 demons with explosive barrels.
This level is packed with explosive barrels. You’ll find a large supply after dropping down to the bottom of the facility during the main meat of the level. Lure fodder enemies close then shoot the barrels instead.
- Skeleton Key: Open 2 Secret Key doors.
There are two Skeleton Key doors in this chapter. We’ll detail where to find the key and both doors in the full guide below.
All Collectibles & Secrets Locations | Chapter 12

Secret #1+ Collectible #1 (Codex + Gold x5): After leaving the exploding, red-tinted vents, you’ll exit back into the facility. Go down the hallway and look right to enter a room with a Codex and some gold.
Gold x8: There’s an easy-to-miss cache of gold early in the level. After dropping down in the red-tinted vents and reaching the first Codex, turn around and look at the end of the vents. There’s a large gold pick-up here that you’ll miss if you reach the Point-of-No-Return too early.

Secret #2 + Collectible #2 (Skin): Past the first Point-of-No-Return, you’ll drop into a control room full of working NPCs. Go down the small steps and look left for a vent with a blue marker. Smash through with Shield Charge to find lots of gold and a path to a Weapon Skin.

Secret #3 (Life Sigil): Entering the vent with alternating fireball launchers, you’ll need to use the Shield to progress toward the objective marker. Instead of going toward the objective, go down the vent hallway to the right instead. It leads to a Life Sigil secret.

Demonic Essence: After acquiring the Ravager gun from the Weapon Pod, you’ll enter a hangar area full of enemies. Defeat the Pinky Rider Leader demon to earn +10 maximum health.

Gold x50: Progressing to the objective switch in the bottom floor of the level, you’ll reach a control room with a large gold chest to the right. You can’t miss it.

Secret #4 (Ruby): After riding the elevator lift to the top floor, you’ll need to perform a Shield Jump from a slime-dripping statue to cross a gap. In the next hallway, you’ll encounter Stone Imps and a Battleknight — at the end of the hallway, drop down to find a secret Ruby upgrade item and a small crate puzzle to escape.

Secret #5 (Gold x50): Right after acquiring the Yellow Keycard, a long pit will unlock nearby. Drop down directly across to a climbable wall to access a large gold chest.

Secret #6 (Secret Key): To get the Secret Key, turnaround from the previous secret (right after the Yellow Keycard) and you’ll spot a vent cover with a blue marker. Shield Charge through it and follow the path (don’t miss the bonus Life Sigil) to reach an optional combat area with the Secret Key in the center.

Secret #7 (Life Sigil): On the way to the Secret Key combat arena room, you’ll climb a vent shaft to a green-marked vent cover. Turn around before smashing through to find a Life Sigil.

Secret #8 (Wraithstone): Directly across from the Secret Key room arena, you’ll find a Secret Key door at the top floor of the facility. Go inside to fight a small encounter of tough enemies. Defeat them all and the Wraithstone upgrade item will become available.

Secret #9 + Collectible #3 (Toy): Drop back down to the bottom floor of the facility once you’ve collected the Yellow Keycard and Secret Key. Defeat the enemies then enter the room with the vent entrance where Secret #3 was located. There’s a Secret Key door here to unlock that contains a collectible toy.