When you explore the Stormveil Castle there is a good chance you might come across a locked door. When you manage to find this locked door there is also a good chance that you might be wondering how to open it. Well this is where you need the Rusty Key.
WHERE TO FIND THE RUSTY KEY
In order to find the Rusty Key you will need to head to the Stormveil Cliffside. You can get there by entering the castle by the south entrance, then heading up several sets of stairs.
At the top of these stairs you will find a door we can go through, it will be rather dark inside, there will also be an enemy waiting for you here too.
After you are done dealing with the threat you can find the Rusty Key in here, it is by a corpse in the corner of the room.
If you continue to explore this room you will find a chest containing the Curved Sword Talisman (enhanced guard counters).
The locked door that this key is used for is to the right of the room where you find the Rusty Key. Then from there just dropped down, it is in a dead end area. The door will have a tapestry above it.
Unlocking this door will take you to an upper level where you can find a Fire Grease and a Silver-Pickled Fowl Foot. You can also go outside this way too.