- The Trench Decay Ossuary mask is the Iron Maiden gas mask, found on the Ossuary map.
- Wearing it triggers the Iron Maiden Penance Challenge: you start at 1 HP with 20% slower movement.
- Completing a major objective in this state rewards the golden Iron Maiden mask.
- Buying the Entombed in Steel war bond unlocks the mask instantly, skipping the map search.
- The challenge can only be completed in a lobby you host.
What Is the Ossuary Mask in Trench Decay?
The Ossuary mask refers to the Iron Maiden gas mask, one of the headline additions from Trench Decay's Skyfall update. Hidden on the new Ossuary map, this mask is more than cosmetic flair: putting it on before a raid launches you directly into the Iron Maiden Penance Challenge, one of the toughest self-imposed trials in the game. Players who push through the challenge at 1 HP earn the golden Iron Maiden mask as a permanent trophy of their valor.
Video Highlights:
- The Iron Maiden mask spawns on the new Ossuary map
- Entombed in Steel war bond grants instant mask access
- Challenge sets you to 1 HP and slows you by 20%
- Completing a major objective rewards the golden mask
- The Ossuary also spawns the Jager boss with dual Vickers guns
Gas masks in Trench Decay double as status symbols. The Iron Maiden line is currently the only mask tied to a challenge-based reward, making the golden variant one of the clearest ways to signal skill to other raiders.
How to Get the Ossuary Mask: Step-by-Step
There are two routes to the mask: find it naturally on the Ossuary map, or purchase the Entombed in Steel war bond. Here is the full process from acquisition to golden reward.
Enter the Ossuary Map
Launch a raid on the Ossuary, the new map introduced in the Skyfall update. Search the area carefully to locate the Iron Maiden gas mask spawn.
Alternative: Buy Entombed in Steel
If you prefer instant access, purchase the Entombed in Steel war bond. It includes two armor sets, two unique gas masks, a new shield, and immediate access to the Iron Maiden mask.
Host Your Own Lobby
Start a raid in a lobby you host. The Penance Challenge cannot be completed in someone else's lobby, so hosting is mandatory.
Equip the Mask and Start the Raid
Wear the Iron Maiden gas mask when launching the raid. You will enter the Penance Challenge state automatically.
Complete a Major Objective at 1 HP
Survive the run with 1 HP and 20% reduced speed, and finish a major objective. Success grants the golden Iron Maiden mask.
In the Penance Challenge state, nearly any incoming damage is lethal. Avoid open sightlines, skip unnecessary fights, and let cover do the work. The Jager boss's AoE smash will end the run instantly.
The Jager Boss: Ossuary's Deadliest Threat
Any guide to the Ossuary mask must cover the Jager, the new boss that spawns on the Ossuary map. Fighting him during the 1 HP challenge is a high-risk decision most players should avoid until the objective is secured.
| Attack | Description | Counterplay |
|---|---|---|
| Dual Vickers gunfire | Sustained machine gun barrage from both hands | Break line of sight, use cover, flank wide |
| Charge | Rushes at you, smashing through obstructions | Pre-position behind hard cover, sidestep early |
| AoE smash | Massive ground slam, near-guaranteed kill | Keep distance, never stay in melee range |
Gunslinger Route
- Fight at long range
- Peek-fire from cover
- Punish reload windows
Evasion Route
- Skip the Jager entirely
- Focus on the objective
- Best for 1 HP runs
Team Route
- Let squadmates draw aggro
- Support from behind cover
- Coordinate revives
The Jager spawns on the Ossuary regardless of whether you wear the Iron Maiden mask. Decide your engagement strategy before starting the raid, not mid-fight.
Mask Rewards and How They Compare
The Skyfall update and its follow-up mini-update added several notable masks. Here is how the Ossuary mask rewards stack up.
| Mask | How to Obtain | Special Effect | Difficulty |
|---|---|---|---|
| Iron Maiden mask | Find on Ossuary map or Entombed in Steel bond | Starts Penance Challenge | Moderate |
| Golden Iron Maiden mask | Complete a major objective in Penance state | Prestige cosmetic, shows valor | Very Hard |
| Commissar's gas mask | Chance drop from Commissar boss on Keep | Trail effect while walking | Hard, grind-based |
The Commissar's gas mask is the first mask in Trench Decay with a walking trail effect. Drop rates increase with Keep difficulty, so higher difficulties are the efficient grind.
Note that the Commissar drop rolls across the screen like a crate opening in the main menu, and difficulty on the Keep directly raises your odds. Pair these mask hunts with your normal raid rotation to avoid burnout.
Loadout Tips for the 1 HP Challenge
Weapon choice makes or breaks a Penance Challenge run. The Skyfall update weapons offer strong options for a fragile playstyle.
| Weapon | Ammo | Magazine | Why It Fits the Challenge |
|---|---|---|---|
| Double-0 pistol | Light | 14 | Explosive rounds, strong burst from safety |
| MG 08 | Medium | 100 | Sustained suppression without repositioning |
| Lil Timothy | Light | 40 | Incendiary rounds create fire zones that block chases |
| Chauchat | Medium | 20 | Solid mid-range damage from cover |
| Shield (melee) | Melee | N/A | Blocks incoming damage, but 20% slow while equipped |
The shield already slows you 20% while equipped, and the Penance state adds another 20%. Stacking both makes you extremely vulnerable to the Jager's charge, so choose one or the other.
Penance Challenge Run Checklist:
- Host your own lobby before starting the raid
- Equip the Iron Maiden gas mask at raid launch
- Memorize the major objective location on Ossuary
- Pack a long-range weapon like the Double-0 or Chauchat
- Avoid the Jager boss unless the objective forces contact
FAQ
Q: Where is the Ossuary mask found in Trench Decay?
The Iron Maiden gas mask spawns on the Ossuary map, added in the Skyfall update. You can also get instant access by purchasing the Entombed in Steel war bond, which includes two armor sets, two unique gas masks, and a new shield.
Q: What does the Iron Maiden Penance Challenge do?
While wearing the Iron Maiden gas mask at raid start, you are set to 1 HP and slowed by 20%. Completing a major objective in this state finishes the challenge and awards the golden Iron Maiden mask.
Q: Can I complete the Penance Challenge in someone else's lobby?
No. The challenge can only be completed in a lobby you host yourself, so make sure you are the host before launching the raid.
Q: Is the Ossuary mask worth the risk?
If you value prestige cosmetics, yes. The golden Iron Maiden mask is one of the clearest skill signals in Trench Decay, since earning it requires finishing a major objective while surviving at 1 HP against threats like the Jager boss.