Aldia's Keep is a mansion which also serves as a research facility, similar to The Duke's Archives in Dark Souls. It features an outside garden, a long entranceway, and a multi-story lobby containing various items, enemies, and a merchant. At the top level, and behind a caged giant Basilisk, is a room leading to the more sinister research area featuring various enemies and items. Through the end of this area is the area boss, the Guardian Dragon, who guards the passage to the Dragon Aerie.
After obtaining the King's Ring from the Undead Crypt the player passes through the sealed door in the Shaded Woods and gains entry to Aldia's Keep. The player then makes their way through the keep and beyond to eventually reach the Dragon Shrine.
Aldia's Keep once belonged to Lord Aldia, the brother of King Vendrick. It was here that he carried out his experiments on various creatures in search of immortality, and later, a way to recreate the dragons of old.
- Foregarden: In the shack near the entrance to the manor.
- Ritual Site: Hidden behind an illusory wall in the staircase between a room with bookcases and desks and the room filled with acid and dogs. While going down the staircase there will be a small intersection, press the interact button on the wall to your left.
- Lucatiel of Mirrah: If the player has spoken to her in all of her previous locations, she will appear near the first bonfire in the shack outside. Depending on whether or not the she has been summoned and kept alive for three of the four boss fights she is available for, she will react differently. Failing to keep her alive for at least three fights will result in her being afraid of forgetting herself as she becomes hollow. Succeeding will have her thank the player and award her armor set.
- Royal Sorcerer Navlaan: Behind a magic wall at the end of a corridor to the right of the main stairs where the bone dragon is located. The wall can be deactivated by pulling the lever located on the corridor on the left, though be aware that by doing so you will miss out on a quest line that offers several unique rewards. Doing so will also cause the dark phantom of Royal Sorcerer Navlaan to periodically invade your world, one instance being just before the bridge to the Guardian Dragon.
- Dragon Acolyte
- Hunting Dog
- Looking Glass Phantom
- Poison Horn Beetle
- Prowling Magus (SotFS)
- Belfry Gargoyle (SotFS)
- Enhanced Undead
- Ogre (petrified)
- Aslatiel of Mirrah
- Royal Sorcerer Navlaan (if released)
- Mimic (heavy chest)
- The Painting Protector (NG+ or using bonfire ascetic)