This demon Door is the only door that can be used only once by each member of the guild.
This should be the first Demon Door you encounter, especially since there is actually a "Demon Door race" that you can participate during your first years at the guild. You won't be able to enter it, however, until you receive the Lamp at your graduation from the guild and use it in front of the stony face. Once inside, you'll be able to scoop up an Elixir of Life, a Howl Tattoo, and a couple of books.
