Brennenburg Castle was rebuilt centuries before the game takes place by Alexander of Brennenburg in the late 16th century, after it was consumed by a fire. At this time, Alexander was presumably masquerading under a different name. The castle is located deep in the woods of eastern Prussia (most likely in today's northeastern Poland or Königsberg), near the town of Altstadt. For the locals, Brennenburg Castle was a place to fear, as villagers sometimes disappeared, presumably kidnapped and taken to the castle for unknown purposes.
The castle is built of large flag stones and has many stone columns. As expected of the time period, it is lit by candles and decorated with paintings and tapestries though, as mentioned before, the castle's wards have fallen into a state of decay and ruin. When the immense Shadow arrives, it causes parts of the castle to collapse entirely forcing the baron's servants to reinforce weaker structures. While this means that many of the wooden structures are crumbling, much of the stone that makes up the walls and ceilings seems to remain intact, specifically in the back rooms as Daniel draws closer to Alexander.
Brennenburg Castle is a large, almost labyrinthine and rotten compound. At the time of The Dark Descent, many areas of the castle have begun to fall into ruin.
- Rainy Hall (S)
- Old Archives (S)
- Entrance Hall (H) (S)
- Refinery (LR)
- Cellar Archives (HR)
- Archive Tunnels (HR)
- Back Hall (H) (S)
- Prison (HR)
- Cistern Entrance (H) (S)
- Sewer (HR)
- Nave (H) (S)
- Inner Sanctum (S)
- Orb Chamber (S)
(S) Denotes the area is mostly safe. No high-risk encounters with any kind of monsters will occur in these areas.
(LR) Denotes the area is of low risk. Non-hallucinatic encounters with monsters may occur in these areas if one were to loiter.
(HR) Denotes the are is of high risk. Encounters with different kinds of monsters will occur in these areas.
(H) Denotes the area is a Hub. A hub is a large, safe area with doors leading to several other rooms you will have to traverse to to reach your goal.
For the first part of the game, you will not run into any monsters, as the Old Archives and the Main Hall serve as a tutorial of sorts to familiarize the player with the controls. However, in the Archives and Wine Cellar, you have the possibility of seeing your first Servant Grunt without actually having to risk being ripped apart, as it is walking away from you and is not scripted to attack regardless of your actions. The first dangerous encounter occurs in the Refinery, and once you escape the water lurkers (Kaernks) in the Cellar Archives, you should prepare for a myriad of encounters in the Storage and the Prison Blocks.
- The location of the castle Brennenburg, might have been inspired by Brandenburg; A German state located in the north-eastern part of the country. Another reason that might support this is Order of the Black Eagle; An organization Alexander is a member of was founded on January 17, 1701 by Elector Friedrich III of Brandenburg who later became Frederick I of Prussia.
- Nave, Choir, Transept and Chancel are all terms used to describe various sections of a traditional Cathedral. This might or might not be a reference to the medieval era inquisition made by the Roman Catholic Church, as there are torture devices founded in these sections which were used by the church against the criminals.
- The Castle is said to be located in deep in the woods of Eastern Prussia near Königsberg, as the name was mentioned in one of the Notes found in the game.
- The Castle's interior bears striking resemblance to the castles built by Teutonic Knights in medieval times.
- Brennenburg in German roughly translates into 'burning castle'. The village nearby, Altstadt, translates to 'old city' and is a term used to describe the historical part of a city.
- In the Revenge Ending the fate of Brennenburg Castle while not directly shown is audibly heard falling apart as the entire structure collapses once Daniel has left safely.
- As Daniel flees he does not encounter any Grunts, Brutes or otherworldly monsters, the entire place is deserted. Alexander's servants and the Kaernk most probably died after direct contact with the Shadow passing through or cave-ins.
- It is unknown how Daniel managed to escape the castle as some parts of the way were either blocked or crumbled, especially the elevator section, but it can be assumed that there was another way to get back to the surface.