The Unknown Key in The Forge is a one-time item that turns a short side quest into access to one of the strongest early tools in the game. It comes from the Bard’s Lost Guitar quest in Stonewake’s Cross and is used to open a locked gate deep inside The Cave, revealing the Fallen Angel’s Cave and the Arcane Pickaxe.
What the Unknown Key does
The Unknown Key has a single purpose – it unlocks the gate that blocks the entrance to the Fallen Angel’s Cave inside The Cave in Stonewake’s Cross. Once that gate is opened, you can reach the Arcane Pickaxe and buy it for in-game currency.
The key is consumed when you use it. After you open the gate, it disappears from your inventory and cannot be reused on another run.
There is no way to reach the Arcane Pickaxe room without using this key; the locked gate only responds to the Unknown Key reward from Bard’s quest.
How to get the Unknown Key (Bard’s Lost Guitar quest)
The Unknown Key is tied to a single side quest in Stonewake’s Cross called Bard’s Lost Guitar. You need to finish that quest once on your account to receive the key.
Step 1: From the Stonewake’s Cross spawn area, walk east toward The Cave. As you move northeast, pass the Potions Stall on your right; just beyond it is a small campfire with a distraught Bard sitting on the ground. Talk to him and accept the Lost Guitar quest.
Step 2: Face southeast from the Bard and head straight into The Cave entrance. Go down the initial slope until you reach the bottom, where you’ll see the NPCs Nord and Umut The Brave standing near each other.
Step 3: Turn left at Nord and Umut to follow the western side of the tunnel. Look along the left-hand wall for wooden support beams. Between the first two beams, there is a patch of greenery on the rock wall. Walk directly into that greenery; your character drops into a Secret Cave hidden behind it.
Step 4: In the Secret Cave, you’ll find an undead NPC and a skeleton. Bard’s missing guitar lies on the rocks just to the right of the skeleton. Move close and hold the interact button (default E on PC) to pick up the guitar.
Step 5: Climb back out of the Secret Cave the way you came, return to the Bard at the campfire, and interact with him again. Hand over the guitar; he resumes playing and awards you the Unknown Key as your quest reward.
Where to use the Unknown Key in The Forge
With the Unknown Key in your inventory, the next step is to reach the locked gate for the Fallen Angel’s Cave inside The Cave network.
Step 1: Go back into The Cave from Stonewake’s Cross. Once again, move down the starting slope until you reach Nord and Umut at the bottom.
Step 2: This time, turn right at the bottom instead of left. Follow the passage east along the “Inner Cave” route. Keep moving forward until you see the first turn on your right.
Step 3: Take the first right-hand path. This side tunnel leads directly to a locked metal gate in the rock wall. If you miss the first turning, the next right-hand path in the same area also connects to the same gate from the side.
Step 4: Approach the locked gate and hold the interact button (E on PC). The Unknown Key is used automatically to unlock the gate and open the entrance to the Fallen Angel’s Cave.
After this interaction, the Unknown Key disappears from your inventory. The Fallen Angel’s Cave remains accessible for that run, and you can walk inside to reach the Arcane Pickaxe shrine.
How to get the Arcane Pickaxe with the Unknown Key
Inside the Fallen Angel’s Cave, the Arcane Pickaxe is suspended above a formation of stone hands at the far end of the chamber. Interacting with it opens a purchase prompt.
Step 1: Walk from the newly opened gate through the Fallen Angel’s Cave tunnel until it widens into a room with carved stone hands in the center.
Step 2: Approach the floating Arcane Pickaxe between the hands and interact with it. You can buy it for $125,000 in-game currency.
The Arcane Pickaxe is designed as a powerful mid-to-late game mining tool. Its stats are:
| Attribute | Value |
|---|---|
| Mine Power | 115 |
| Mine Speed | +10% |
| Luck Boost | 50% |
| Rune Slot | 3 |
Higher Mine Power and Mine Speed improve how quickly you can break ore, while the 50% Luck Boost increases your chances of better drops. Three rune slots make it one of the more flexible pickaxes for rune builds in Stonewake’s Cross and beyond.
Key limitations and common questions
Is the Unknown Key reusable?
No. The Unknown Key is a single-use item. Once you unlock the Fallen Angel’s Cave gate, the key is gone and cannot be used again on another gate or run.
Can you reach the Arcane Pickaxe without the Unknown Key?
No. The gate to the Fallen Angel’s Cave does not open through any other method. Every player who wants the Arcane Pickaxe must complete Bard’s Lost Guitar quest at least once to obtain and use the Unknown Key.
Do you have to redo Bard’s quest on later visits?
The Unknown Key is only needed to unlock the gate. Once that is done for your current progression, you simply walk back through the open entrance to revisit the Fallen Angel’s Cave and the Arcane Pickaxe location; the quest itself does not need to be repeated for that unlock.
The Unknown Key looks mysterious at first, but it is simply the bridge between an easy side quest near Stonewake’s Cross spawn and a high-value mining tool hidden behind a locked gate. Complete Bard’s Lost Guitar quest, follow the right-hand path in The Cave, and you convert a short detour into long-term mining power with the Arcane Pickaxe.
