You can't speak of how blues music relates to rock and roll without including the names Johnson or James.

Robert Johnson is rumored to have made a deal with the devil. 

For his soul Robert would get the great ability to play guitar but for Skip James the allure of Satan was something different.

Skip wanted to be the devil himself because the devil had taken the love of his woman. She had became in his eyes evil.

Years later a Birmingham band by the name of Black Sabbath claimed to have sold their souls for rock and roll.

Maybe Black Sabbath didn't directly get influenced by Robert and James to write the music they wrote however the allure of the dark side is the same.