|“||A tin-forged key with the symbol ♃ carved into it. This symbol means "Jupiter."||”|
The Jupiter Key is a key in Haunting Ground. Fiona Belli obtains the key when she solves the Dragon Room puzzle and ascends the frozen pillar that leads up to the library; kicking a ladder and knocking it down.
The key unlocks the dual doors that works as a puzzle; touching the wrong items within the room would trap and kill Fiona instead of rotating the carousel and lowering the bridge leading to the cemetery.