The Devil is decidedly bad news, Fundamentalist Christians believe Satan takes possession of people and makes them do horrible things. Then fundamentalist Christians do horrible things to try and get the devil out of those they imagine are possessed. In Texas forcible exorcism is legal or was legal in 2008, PZ strongly disapproves. 
The devil is also Global warming denialist organisation the Heartland Institute, PZ has no sympathy for that devil. 
The devil in the shape of the Templeton Foundation is seductive. Templeton offers vast wads of cash to anyone who hopes or imagines scientific research leads to God. PZ goes after that devil.