Slay the Spire 2 Multiple Lantern Keys — How the Stacked-Key Trick Works
Published 2026-05-15Updated 2026-09-194 min read
Duplicate Lantern Keys in Slay the Spire 2: how card duplication copies a Quest card, why holding two keys lets you take both War Historian Repy rewards, and the multiplayer exception.
One Lantern Key buys one reward. Two Lantern Keys buy both — and since a 2026 beta patch, stacking the key has been an intentional, if well-hidden, mechanic. Here is how the stacked-key trick actually works, stripped of the forum rumors.
The rule: one key per reward
At War Historian, Repy in Act 3, the two options each consume a Lantern Key:
- Unlock the Cage → the History Course relic
- Unlock the Chest → 2 random potions + 2 random relics
Choosing an option for the first time consumes exactly one key. The secret is in the fine print: if you still hold another Lantern Key after your first pick, the other option unlocks too — you take the cage and the chest, and every remaining copy of the key is then removed from your deck.
How do you get a second key?
The Lantern Key is a Quest card, and Quest cards can be copied like any other card in your deck. Duplication effects and events that add a copy of a deck card can clone the key, and players who deliberately build around the trick grab that duplication when it is offered. It is niche, but the payoff — both Repy rewards in one run — is the single richest event payout in the game.
The developers are in on it: patch notes since V0.105 confirm "something special now happens if you have multiple Lantern Key cards," and later patches cleaned up the interaction so all duplicates clear properly after the event.
The multiplayer exception
The stacked-key trick is single-player only. In co-op, the double-reward interaction is disabled even if every player in the party is holding a key — the first pick consumes one key and the chain ends.
Is the key worth duplicating at all?
Honest answer: usually not on purpose. The key is an unplayable card clogging a deck slot for an act, and most duplication effects are worth more on a real card. But if a duplication event shows up early in Act 2 after you have taken the key, the copy turns a good event reward into a great one — and History Course plus two extra relics is a run-warping haul.
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