There are only 4 simple keys located in all of Hollow Knight. Most of them are very simple to acquire and you are able to get the keys at about the same time as you find the locks.
Requirements:
Desolate Dive or Lumafly Lantern
Where are all the Simple Keys in Hollow Knight?
- Bought from Sly in Dirtmouth for Geo 950
- If you have not found Sly yet, check the map below. Once you talk to sky he will open up shop in Dirtmouth and sell some items to include a simple key
- Found in the City of Tears just below the City Storerooms. The Simple Key is located in the topmost alcove on the right of the room
- In the Ancient Basin, on the dead body of a Royal Retainer inside a Mawlurk corpse
- Obtained by killing the Pale Lurker in a hidden area behind the Colosseum of Fools
- Make your way over to the Coliseum of Fools
- Once there, jump into the cage below the colosseum
- Head to the far right and up one room. You will be at the back side of the colosseum and there is a breakable wall
- Once you get through, drop to the bottom, find and defeat an enemy known as the Pale Lurker who is holding the simple Key
Once you have all 4 simple keys there are 4 doors that can be opened:
- Locked door far right in Dirtmouth
- The Pleasure House in City of Tears
- The Royal Waterways
- The Pantheons
For a video on where to find all of the Simple Key Doors, click here: https://youtu.be/DOskVvR42zc
