I think it's basically about people that want the band to fail. The analogy they use for this is this guy who is about to push the "devil" off the roof hene the title "Speak of the Devil" the guy is obviously adtr and the devil represents the people that want the band to fail, "This is my vengeance for all the wrongs you've formed against us you always get me wrong" Obviously its really about standing up for yourself. I sincerely doubt this song has anything to do about suicide let alone murder I think these are all just analogies. As for the choruses I believe that while it references murder, "I'm on the edge of the rooftop thinking nobody will ever know I hope that you'd want to be the one to see the distance from the road" it is purely analogical.