Enemy is related to Opponent. Opponent is related to Competition. Competition is related to Big. Big is related to Galaxy. 
Shell is related to Defense. Defense is a type of Organization. Organization is the opposite of Chaos. Chaos is related to Random. 
Enemy <--RelatedTo--> Opponent <--RelatedTo--> Competition <--RelatedTo--> Big <--RelatedTo--> Galaxy 
Shell <--RelatedTo--> Defense --IsA--> Organization <--Antonym--> Chaos <--RelatedTo--> Random 