Moons of Peril Drop Simulator

How Lunar Chests work

The chest sits in the Ancient Shrine in Neypotzli. First unlock requires beating all three Moons of Peril once; after that you can loot it after defeating at least one. This simulator assumes the chest is already unlocked.

Each defeated moon gives an independent 1/56 roll at that moon’s set. If that hits, the piece is chosen uniformly from the pieces you have not obtained yet (or any piece once the set is done). You can receive uniques from two or three moons in one chest. Getting any unique skips the standard table.

The three sets

• Eclipse — ranged (atlatl). Weak to stab while fighting the boss.
• Blood — melee (dual macuahuitl, Bloodrager set effect). Weak to slash.
• Blue — magic (spear, Frostweaver set effect). Weak to crush.

Standard loot

If no unique drops, the chest rolls a 30-weight table: atlatl darts (5), swamp tar (4), sun-kissed bones / supercompost / soft clay / grimy harralander (3 each), blessed bone shards / water orbs / maple seeds (2 each), and wyrmling bones / grimy irit / yew seed (1 each). Roll count is 1, 3, or 6 depending on moons defeated.

Rates at a glance

• Unique per moon: 1/56, then 1 / remaining pieces in that set
• Displayed rate per specific piece: 1/224 (ignores duplicate protection)
• At least one unique with 3 moons: ~1/19
• Expected chests for all 12 uniques: ~320

Pair with the drop rate calculator for “chance by KC” math, or the Barrows chest simulator if you are comparing other set grinds.

FAQ

What is the unique chance per Lunar Chest?

Each moon you defeated rolls independently at 1/56 for a piece from that moon’s 4-item set. With all three moons, the chance of at least one unique is 1 − (55/56)³, about 1/19. The wiki lists each specific piece as 1/224 (56 × 4), ignoring duplicate protection.

Can I get standard loot and a unique in the same chest?

No. If any unique drops, the standard table is skipped entirely. Otherwise you get 1 roll for one moon, 3 rolls for two moons, or 6 rolls for all three.

How does duplicate protection work?

Until you have all four pieces from a moon, a unique roll from that moon only picks among pieces you do not have yet. After the set is complete, any of the four can drop again. Protection is per moon, not across moons.

How many chests to finish all three sets?

The wiki expected value is about 320 chests with all three moons each time. Half of players finish around 305; 90% by about 463.