The Lantern Key, Explained

The Lantern Key is one of the sequel's chained secrets: an event choice in one act that changes what you can find in the next. Here is exactly how it works, from the game files.

The event

[[event:The Lantern Key]] appears in Act 2 (the Hive). You find a faintly glowing key, and a stranger who looks like bad news claims it. Two choices:

• Return the Key: gain 100 Gold. The stranger thanks you and rewards you handsomely. Safe, done, no key.
• Keep the Key: fight the stranger to keep it. Win the combat and the [[Lantern Key]] joins your deck as a card.

What the card does

The Lantern Key card's whole text is: "Unlocks a special event in the next Act." It is not playable in combat; it rides in your deck as a pass. Reach the next act with it and a special event becomes available on your map that runs without the key never see.

Should you keep it?

Treat it as a bet priced at 100 gold plus one fight's worth of HP. If your deck is healthy at the Act 2 midpoint, the fight is affordable and a bonus act 3 event is usually worth more than 100 gold, extra events mean extra chances at relics and removals when they matter most. If you are limping, take the gold: 100 at a shop is a card removal or a potion, and dead climbers unlock nothing.

One caution for lean decks: the key is a card. Until it leaves, it occupies a draw like any other card, so ultra-thin combo decks pay a small consistency tax to carry it. For most decks that tax is invisible.

The events index has every event's full choices and outcomes, and the boss guide covers what act 2 will throw at you on the way to spending it.