Beneath the castle's foundations are a series of caverns where the Illuminados mined the fossilized remains of the ancient Las Plagas parasites. Within the castle itself is an entire army of zealots under Salazar's command and the structure itself is fortified with numerous death traps such as flame-throwing statues, enormous guillotines, even a huge robot statue of Salazar himself.
- Dining gallery - A dining hall filled with a long dinner table and decorated with various paintings.
- Hall of Armour - A series of chambers all decorated with suits of medieval armour. These suits aren't merely decorations but Armadura B.O.W.'s that protect a key item needed for Leon to progress through the castle.
- Hedge maze - The castle's garden consists of a large hedge maze as well as ornate marble statues and a fountain. Within the maze are a number of treasure chests on pedastals that contain items Leon requires to continue further. The maze is patrolled by Salazar's pet Colmillos hounds.
- Sewers - Salazar is known to execute his underlings by dropping them down here. Leon survived falling into this pit only for Salazar to send one of his Verdugo lapdogs to hunt him down.
- Dungeons - The castle dungeons are flooded and dilapidated, with collapsed walls and rusted cell bars. It seems that the cells still end up being occupied despite the area's state of disrepair. The dungeons are crawling with Novistadors that prey on anyone that enters their domain.
Below is a list of all the monsters that reside within Castle Salazar.