- "This place looks like a shrine to that strange warrior…"
- ―Kit Fisto
Grievous's castle was the personal retreat of the cyborg Supreme Commander of the Confederacy of Independent Systems, General Grievous. Located on the third moon of the Outer Rim world of Vassek, the castle was built into the rockface of a large gorge. Shrouded by the moon's heavy fog, Grievous's castle was specifically designed to cater to the needs of the general, with an operating and repair room, a hangar for his starfighter, and several booby traps intended for intruders. Aside from Grievous, the castle was the home to the general's repair droid EV-A4-D, Gor, Grievous's pet roggwart, and a cadre of IG-100 MagnaGuards who protected the lair.
Around 22 BBY, Grievous's sanctuary was infiltrated by Republic forces under the command of Jedi General Kit Fisto and Jedi Knight Nahdar Vebb. The Republic forces were trapped inside the castle by General Grievous, who locked down the facility. The general hunted the Jedi and their clone troopers through the castle until only Kit Fisto remained. Fisto was able to disable the castle's control system and end the lockdown, allowing him to escape the third moon of Vassek and General Grievous's wrath.
- "Why don't you come out, General? Show us some of that Separatist hospitality."
"Patience. In the meantime, please experience all my home has to offer. It has been prepared for uninvited guests, like you."
- ―Kit Fisto and Grievous
Grievous kept a favored pet roggwart named Gor at his castle. The halls of the building were adorned with statues depicting the General  as a Kaleesh warrior with mechanical limbs. An extensive warehouse was stacked with replacement parts for the mechanical general, and Grievous kept the caretaker droid EV-A4-D on hand for times when he was injured and needed replacement droid parts installed. Other areas of the castle included the arena in which Grievous kept his pet roggwart Gor and another area where he stored trophies taken from dead Jedi. His castle also included a control room where he could monitor the halls. From the control room he could activate various traps including releasing Gor and triggering a trap door leading to a molten incinerator vat. The control room's door could only be opened by pressing a number of buttons in the correct order.
- Star Wars: The Clone Wars – "Lair of Grievous" (First appearance)
- Path of the Jedi (Non-canonical appearance)
- Star Wars: The Clone Wars: Republic Heroes (Nintendo DS edition)
- Star Wars: The Clone Wars: The Visual Guide (First mentioned)
- Star Wars: The Clone Wars: Visual Guide Ultimate Battles
- The Art of Star Wars: The Clone Wars
- Galaxy at War
- Star Wars: The Official Starships & Vehicles Collection 37