If God be the creator of all things, Is the devil a thing? Are thoughts things?

We don't have very much information on Heaven during that time, but it's almost certain that God set some rules. And as it states in Romans 5, sin takes advantage of the law, but God uses the sins for His own purpose on showing His glory. So basically, the Devil took advantage of the law and rebelled, so God banished him. Now God is using that sin to show His greatness everyday. Sorry that it's hard to explain.