Yes I am dealing with Nightmares (Fears ). So Pretty much if you see your fear in a nightmare.. He would be responsible for it. Spiders, Falling bolders, Your wife or husband killing you, Your children becoming monsters or children running away.. All kinds of fears you have in your nightmares.. I would think he would be dealing with them.

Wait how can you make a Nightmare world.. When you are in charge of dreams and a dreaming world ?