Fog Castle is the first immortal dungeon that Django explores in Boktai: The Sun is in Your Hand. The Count is supposedly recovering from the wounds that were inflicted upon him in a battle against Django's father. The immortal boss is the Count (although you don't actually fight him), resting in his coffin and surrounded by bats; however, it turns out that this is actually a decoy used to distract Django and Otenko while the real Count recovered from his wounds in Bloodrust Mansion. After purifying the decoy you get the Fool Card.
- This dungeon is featured in the E3 comic trailer, where two brothers are playing through it.
- The comic shows some rooms in Fog Castle that are not present in the actual game.