What the game says, what really changes when you play, and the code to unlock it. Steam says 2.7% of players have it.

Artifact of Prestige
Game text: «At least one Shrine of the Mountain spawns every stage. Shrine of the Mountain effects are permanent.»
Every stage has at least one Shrine of the Mountain, and its effects are permanent: every shrine you use adds one more boss (and more items) to every teleporter after it.
The more you use, the more bosses: after five stages, five or six bosses per teleporter. Lots of loot and lots of danger. It arrived with Seekers of the Storm.
It arrived with the Seekers of the Storm expansion. 2.7% of all Risk of Rain 2 players on Steam have it, from Steam's public stats on 31 October 2026.
Read top to bottom, as shown here: three rows of three shapes. Each slot on the generator changes shape when pressed, in this order: square ■, circle ●, triangle ▲, diamond ♦.
In co-op, the group can enable any artifact that any player has unlocked. Artifacts are chosen in the menu before the run starts.
Enter its code (▲●● / ■●▲ / ●●■) in the Compound Generator on Sky Meadow or Helminth Hatchery, use the laptop and beat the Bulwark's Ambry trial: take the key and break the reliquary.
Every stage has at least one Shrine of the Mountain, and its effects are permanent: every shrine you use adds one more boss (and more items) to every teleporter after it. The more you use, the more bosses: after five stages, five or six bosses per teleporter. Lots of loot and lots of danger. It arrived with Seekers of the Storm.
2.7% of all Risk of Rain 2 players on Steam have it, from Steam's public stats on 31 October 2026.
Sources: the game's English text (artifact name and description), the Risk of Rain 2 wiki (riskofrain2.wiki.gg: the Artifacts page and this artifact's page, read on 31 October 2026; code, Compound Generator and Bulwark's Ambry) and public Steam stats. The plain-words text is ours. Icons: Risk of Rain 2 (Hopoo Games / Gearbox).