What does the Lantern Key do in Slay the Spire 2?

What does the Lantern Key do? Delayed rewards aren't always worth it in Slay the Spire 2 - often they give you some money, or sometimes a card - but when we say that the Lantern Key is worth going for, we really mean it. The prerequisites to obtaining the reward are tough, but we have found it to be an absolute game-changer every time we earned it.

It doesn't matter which Slay the Spire 2 character you're playing as; the Lantern Key is an absolute must. While things like the Byrdonis Egg can add a little oomph to your damage output, the reward from the Lantern Key quest is a relic that can add a whole new dimension to your attack. Here's how to get the Slay the Spire 2 Lantern Key and what its eventual rewards are.

There's a random event you can come across that sees you picking up a faintly glowing key, and a mean-looking knight promptly asks you to hand it back. You have two choices here: hand the key back and pocket 100 gold, or fight the knight to keep the key.

The knight fight isn't too tough, although you may want to be wary if entering the battle with low health, as they attack constantly. Once you defeat the armored enemy, you'll receive the Lantern Key.

The Lantern Key activates a special event in the next act, so for now, you're stuck with the key in your deck. It acts as a curse of sorts, as it will appear in battles but is unplayable. Proceed to the next act, and you will eventually meet the war historian, Repy, who is trapped in a cage.

When you meet Repy, you're given two choices: use the Lantern Key to unlock the cage they're trapped within, or use the Lantern Key to unlock a chest. You can only choose one. Unlocking the chest rewards you with two random potions and two random relics, but releasing Repy grants you the History Course relic.

This powerful relic plays a copy of your last played attack or skill at the start of your next turn. This can double your damage output, and it offers some unique opportunities with skills, allowing you to set up for a huge swing attack later on. Every character in STS2 benefits from this incredibly powerful relic, so try to grab it whenever the opportunity arises.

Now that you know what the Lantern Key does, you can decide whether to go for the History Course relic or not. Although it's a bit more involved than other quest cards in the card game, we highly recommend picking it up when you can, as it'll help create the best builds imaginable.