Krull offered a lot more inspiration than just the Glaive – though that was mighty cool. The thing is, much of the objects of inspiration in Krull were themselves inspired by myth or other fantasy properties. Now the Beast’s teleporting castle probably was borrowed from some other source, but for me it belongs to Krull.
For those not in the know, the villain of Krull was called “the Beast” and he was kind of like Sauron (of the books) in that he was impressive yet absent. His Black Fortress would teleport to a different location each sunrise. From his Black Fortress he would send out his Black Riders . . . er Slayers to conquer the people of Krull (though that’s a good name for a barbarian, it’s the name of the planet).
Having a teleporting bad guy hideout helps with a few things. It makes the baddie extra mysterious and dangerous, considering he can appear anywhere and therefore nowhere is safe. Even if the PCs can gather an army big enough, there is no geographic focal point to attack. And if they do get in, where will they be when they get out.
But my favourite part about borrowing the idea of the Black Fortress are the quests on which the PCs can embark upon just to find the place. That’s most of the movie in Krull. And given that the Beast is an alien force, and his Slayers combine good old-fashioned fantasy terror knight with lasers, the quests might lead to more than just the next continent. This might be a good way to introduce magical interplanetary travel, or even inter-dimensional travel. If you are doing D&D, that could mean Spelljammer or Planescape.
Finally, when the PCs are triumphant, the Black Fortress might become the White Fortress, and become a teleporting base of operations that could take the PCs to distant realms or distant planets where they might find lands governed by completely different gods or magical systems.
Kind of better than capturing Barad-dur or Mount Doom.
You find more Edge of Inspiration articles here.
You can read more about Krull on Wikipedia or IMDB.
You can read more about Spelljammer and Planescape at Wikipedia.