The Kingkiller Chronicle—Valaritas?
"It was quite by accident that I found the four-plate door.
It was made of a solid piece of grey stone the same color as the surrounding walls. Its frame was eight inches wide, also grey, and also one single seamless piece of stone. The door and frame fit together so tightly that a pin couldn’t slide into the crack.
It had no hinges. No handle. No window or sliding panel. Its only features were four hard copper plates. They were set flush with the face of the door, which was flush with the front of the frame, which was flush with the wall surrounding it. You could run your hand from one side of the door to the next and hardly feel the lines of it at all.
In spite of these notable lacks, the expanse of grey stone was undoubtedly a door. It simply was. Each copper plate had a hole in its center, and though they were not shaped in the conventional way, they were undoubtedly keyholes. The door sat still as a mountain, quiet and indifferent as the sea on a windless day. This was not a door for opening. It was a door for staying closed.
In its center, between the untarnished copper plates, a word was chiseled deep into the stone: VALARITAS.”
And when Kvothe speaks with Master Elodin about it:
“’What about the stone door in the Archives?’ I asked. ‘The four-plate door. Now that I’m a Re’lar can you tell me what’s behind it?’
Elodin laughed. ‘Oh no. No no. You don’t aim for small secrets do you?’ He clapped me on the back as if I’d just made an especially good joke. ‘Valaritas. God. I can still remember what it was like, standing down there looking at the door, wondering.’
He laughed again. ‘Merciful Tehlu, it almost killed me.’ He shook his head. ‘No. You don’t get to go behind the four-plate door.’”
The third book is called The Doors of Stone. That’s right—Doors—not just Door. This obviously means that there is more than one door of stone. It is still open for interpretation whether or not the Valaritas door in the archives really is one of the doors of stone to which the title refers. After all, I’m sure that in the world of the Four Corners there are many doors fashioned out of stone.
This makes me wonder, though, if the door in the archives is one of the doors, what or where is the other door? Is it a door that lies just beyond the four-plate door, and is a second entry point or a second level? Or is it a door on the opposite side of wherever the four-plate door leads? Like the pair of vanishing cabinets in Harry Potter and the Half-Blood Prince, what if the pair of doors of stone is a type of portal that leads somewhere? And if that’s true, where do the doors of stone lead to?
As an afterthought, the initial description of the four-plate door also reminds me of Kvothe’s seamless and mysterious thrice-locked chest, which also has at least one copper lock.