The Plague Doctor Mask is an accessory item in Remixed Dungeon that grants permanent immunity to toxic and paralytic gases when equipped. It is the starting ring accessory for the Doctor class and is also obtained by completing the Plague Doctor NPC quest.

A carved ebony mask shaped like a ravenous skull, fitted with amethyst gemstones in the eye sockets and lined with herbs and spices. Wearing it filters the air you breathe through a labyrinth of tubes and filters, masking the stench of decay that clings to you like a shroud.

• Type: Accessory (artifact slot)
• Covers Facial Hair: true
• Covers Hair: false
• In-App Purchase: No (`nonIap() == true`)
• Obtainability: Unlocked when Badge.DOCTOR_QUEST_COMPLETED is earned
• Equipment Slot: Artifact (via `RPD.Slots.artifact`)
• Price: 20 gold
• Sprite: Index 26 in `items/artifacts.png` (also Java `image = 23` in artifacts sheet)

• Gases Immunity: When activated, permanently applies the Gases Immunity buff to the wearer
• Buff Removed on Unequip: When deactivated, the Gases Immunity buff is removed
• Cosmetic: Covers facial hair and visually equips on the hero sprite layer (via `Accessory.getLayerFile()`)

• Starting Accessory for Doctor: Provided as the `ring1` slot in `initHeroes.json` for the `DOCTOR` class
• Quest Reward: Obtained by completing the Plague Doctor NPC quest line, which unlocks Badge.DOCTOR_QUEST_COMPLETED
• Ownability Gate: `haveIt()` requires Badge.DOCTOR_QUEST_COMPLETED to be unlocked (or donation level 4 from the base Accessory class)

• Java Class: PlagueDoctorMask.java
• Parent Class: Accessory.java
• Hood Variant: PlagueDoctorMaskHood.java
• Lua Script: PlagueDoctorMask.lua — handles activate/deactivate and the GasesImmunity buff
• NPC Source: PlagueDoctorNPC.java
• Hero Definition: initHeroes.json — `ring1.kind = “PlagueDoctorMask”`
• Badge: Badges.java — `Badge.DOCTOR_QUEST_COMPLETED`
• English String Resources: PlagueDoctorMask_Name, PlagueDoctorMask_Info in `values/strings_all.xml`
• Russian String Resources: `PlagueDoctorMask_Name, PlagueDoctorMask_Info` in `RemixedDungeon/src/main/res/values-ru/strings_all.xml`
• Other Localizations: Available in de, fr, uk, ko, el, and other supported languages
• mr: namespace: plague_doctor_mask_item for machine-readable references

• Doctor Class — only class that starts with this accessory
• Plague Doctor NPC — quest provider
• Medicine Mask — earlier quest reward (cosmetic)
• Bone Saw — Doctor starting weapon
• Artifacts — general artifact documentation