One of the Dimir's major locations is well known throughout Ravnica: the officially guildless Ismeri Library. The library is open to all citizens and is run exclusively by Dimir guild members. Many guilds—namely the Azorius , Orshov, and Boros —all know there must be something going on within the library walls, but they have not been able to figure out what. The thought of crimes being committed in plain sight drives them mad as they try to decipher and detect what the Dimir are up to. The Ismeri Library is one of the centers of Dimir communication. Messages are magically hidden within the hundreds of thousands of books stored here. Dimir agents use the library to trade messages, gathering message fragments taken from across several documents. Ravnican citizens never know if the book or scroll they're reading might contain encrypted messages that spell out Dimir assignments, directives, or assassination targets.