Quick Answer
The Stone Key is used to open a hidden coffin inside the Ancient Ruins during A Hero’s End.
The coffin contains The Hand of Fate shortsword, Ancient Hero’s Ring, and several additional items.
If you already have the Stone Key, this is the route:
- Go to the Ancient Ruins connected to A Hero’s End.
- Enter the ruins at night.
- Take the Ancient Key from the barrel beside Father Florin if you still need access.
- Enter the ruins and defeat the Ancient Guardian.
- Follow the deeper route through the ruins using Shadowstep.
- Defeat the Kobolds near the final room.
- Enter the room containing the hidden coffin.
- Use the Stone Key on the coffin.
- Collect The Hand of Fate and the other rewards inside.
The Stone Key itself is found earlier in the Svartrau Cathedral Treasury, so the place where you find the key and the place where you use it are completely different.
Where Exactly Do You Use the Stone Key?
The Stone Key belongs to a hidden coffin inside the Ancient Ruins explored during A Hero’s End.
This is why the key can be confusing.
You find it beneath the Cathedral Treasury, but there is no Stone Key lock you need to search for inside the Cathedral itself.
Instead, keep the key until you reach the Ancient Ruins.
The coffin is located deep inside the ruins, beyond the Ancient Guardian and a section that requires Coen’s vampire traversal abilities.
How Do You Reach the Stone Key Coffin?
The important part is to make this trip at night, because you will need Shadowstep to reach the hidden area.
Once you reach the Ancient Ruins:
- Take the Ancient Key from the barrel beside Father Florin.
- Use it to unlock the entrance to the Ancient Ruins.
- Squeeze through the narrow opening between the walls.
- Defeat the Ancient Guardian.
- Turn left and follow the path to the end.
- Turn left again.
- Use Shadowstep to cross the gap in the floor.
- Continue forward and use Shadowstep to climb the wall.
- Keep moving through the ruins.
- Shadowstep north toward the open doorway.
- Defeat the Kobolds in the next area.
- Enter the room ahead.
The hidden coffin is inside this room.
Walk up to it and use the Stone Key to open it.
What Do You Get From the Stone Key Coffin?
Opening the coffin gives you:
- The Hand of Fate — Shortsword
- Ancient Hero’s Ring
- Silver Mug
- Ancient Healing Salve
The main prize is The Hand of Fate, so the Stone Key is worth using even if you are not trying to collect every optional item in the Ancient Ruins.
Where Do You Find the Stone Key?
If you know where the key is used but haven’t actually found it yet, the Stone Key is hidden inside the Svartrau Cathedral Treasury.
Getting it requires two stages: first entering the Treasury, then finding its hidden lower room.
How to Get the Stone Key
- Get the Cathedral Treasury Key from the Belltower in The Cathedral Complex.
- Go to the northern garden of the Cathedral.
- Use the Treasury Key to enter the Cathedral Treasury.
- Go through the second door.
- Turn left and interact with the bookshelf.
- Push the bookshelf aside to reveal a secret area.
- Climb down the ladder.
- Open the hatch below.
- Activate Focus Mode.
- Inspect the highlighted objects.
The Stone Key is sitting on a stone in front of the cross in the hidden room.
Do You Need the Stone Key for A Hero’s End?
No. The Stone Key is not required to complete A Hero’s End itself.
It is used for an optional hidden coffin inside the Ancient Ruins.
You can still get the Ancient Hero’s Armour without the Stone Key.
So if you already completed or explored the quest without opening the coffin, that does not mean you did something wrong.
The Stone Key is primarily there to access the additional loot hidden inside the ruins.
This also means you should keep the Stone Key if you find it before reaching A Hero’s End rather than worrying that you missed its use somewhere in the Cathedral.
Do You Need to Complete In the Name of the Father First?
No. You can access the Ancient Ruins without completing In the Name of the Father.
An Ancient Key can be found on a barrel beside Father Florin.
That key opens the entrance to the Ancient Ruins.
Even if your interaction with Father Florin ends differently, you can still explore the ruins and reach the hidden coffin afterward.
Can You Use the Stone Key During the Day?
The Stone Key itself is not the main problem — reaching the coffin is.
The route through the Ancient Ruins requires Shadowstep, so you should make the trip at night while Coen has access to his vampire abilities.
If you are standing in the ruins during the day and cannot follow the route toward the hidden coffin, return at night rather than assuming you have the wrong key.
Is the Stone Key Worth Using?
Yes, especially if you want unique weapons and equipment.
The key has a very specific purpose and leads directly to:
- The Hand of Fate
- Ancient Hero’s Ring
- Silver Mug
- Ancient Healing Salve
You do not need to choose between several different locks or save the Stone Key for something better later.
Its intended use is the hidden coffin in the Ancient Ruins.
