Caches are items that are very precious to Councillors. They look like small glass spheres with seven coloured gems inside of it; some silver, some gold, and some black; they hold memories that are too dangerous for even the Councillors to have. When a particularly secret or painful memory occurs Councillors place these memories into the cache (probably through some type of Telepathic method) before having the memory erased from their minds. The erased memories are called the Forgotten Secrets and need to be well protected as they can throw the Elvin world into chaos. Each Councillor guards their cache with their life.
Care and Keeping of Caches
To keep caches extra safe they are often stored in 'the void'. Edaline explained in book 4 that everything in the universe is connected through strings of energy; and the void as a a place where all of the strings meet up. Conjurers are able to pull on the strings to bring whatever is on the other end of the string to them. Conjurers can also put things (like caches) into the void and attach an energy string to whoever the cache belongs to. When the person whom the cache is attached to mentally pulls on the string the cache is pulled out of the void. This is why Councillor Oralie appeared to be a conjurer at the beginning of book 4; because she was pulling Kenric's cache out of the void. The person to which the cache is attached to must be able to hold onto the cache where ever they hide the other end in their mind. If they should lose hold on the cache there is an additional protective measure where a key word/ phrase can be spoken in the cache holders voice and the cache will appear. This safety measure only works once.