Ancient Peoples' Mask is the Epic head piece in Windrose. It is an Epic head slot item obtained through exploration rather than a standard crafting recipe.

Overview
Rarity: Epic
Slot: Head
Set: Standalone (no set bonus)
Item Level: ilvl 1
In-game description
"Ancient Peoples' Ritual Mask."
Defense
300 DEF at Item Level 1. Epic-tier armor pieces use the 300 DEF baseline rather than the 100 DEF of Rare and Uncommon pieces.
Set bonuses
The Ancient Peoples' Mask is a standalone head slot item and does not belong to a multi-piece set. It offers no 2-piece or 4-piece bonus but provides a high 300 DEF at Item Level 1, far above the 100 DEF baseline of Rare pieces.
Notes
The mask was originally labeled Senkamati Ritual Mask in pre-release game data (100 DEF, then 420 DEF at Item Level 7) before being renamed to Ancient Peoples' Mask with a settled 300 DEF value in game version 0.7.0.0.
Community reports describe it as a drop from exploring ancient ruins in the swampy biomes, but a canonical source location is not currently documented in game.
See also
Armor and Equipment: Windrose armor system, slots, and rarity tiers
Armor and Clothing Workshop: crafting station for every armor piece