Enemy is related to Thing. Thing is a type of Substance. Agent is a type of Substance. Agent is related to Investigator. 
Classical is related to Fire. Fire is related to Ash. you are likely to find Ash in/at/on Air. you are likely to find Pollution in/at/on Air. 
Enemy <--RelatedTo--> Thing --IsA--> Substance <--IsA-- Agent <--RelatedTo--> Investigator 
Classical <--RelatedTo--> Fire <--RelatedTo--> Ash --AtLocation--> Air <--AtLocation-- Pollution 