Well, after what happened in Vegas, it could be said they are Stephen Paddock level evil. Paddock Heads? Paddocked? Not really fair to the other people with the same last name though who did nothing wrong.
I generally don't like to give someone so evil the notoriety by saying their name but since the similarities are so striking I made this one time exception.
I just can't think up one and Satanic just doesn't have the right "vibe" either.
Perhaps there's an old, not used any more word, that would fit.