"They're many names given to the things of this vast consciousness that we don't understand, are afraid of, or otherwise just don't want to be associated with. These creatures, though familiar in appearance to many common races, have no name for themselves, but have been appropriately named "Concordare Iram", Translated: Harmonized Rage."
The PCs encounter a strange set of artistic drawings done on the ground as they pass through a city. It has been done in chalks and no one saw who did it. Wizards might recognize the writing within the colored square as an obscure and dead language with a message stating that a prominent wizard and a retired bard have discovered how to populate Arcadia with the spirits of the dead!
Is it a local hoax, or are the PCs crossing the path of a very deranged and possibly dangerous mage?