"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."
In the harbour of a major city a large and terrifying ship made of human nails docks. Nobody seems to inhabit this ominous vessel, someone needs to go on board and unveil the mystery. In comes the PCs.