Black Sabbath was a 1970s death metal group. They made some classic heavy metal songs that were influential to heavy metal such as the seven minute long song about the end of the world brought about by stupid generals referred to as “war pigs” who nuke the planet.
They also made the song called Iron Man about a man who travels forwards in time and comes back to his time again to save the world but encounters a metal field that turns his body into metal. Nobody listens to him because he can not talk with a metal mouth, and he is ostracized by society due to his creepy appearance. He kills the people for rejecting him and realizes that he is the end of the world that he was trying to warn the people about. The song was used in the Iron Man movies with Robert Downey Jr. as a theme song and was featured prominently during the credits at the end of the first Iron Man movie.
Black Sabbath made a song that was inspired by a supposed encounter the bass player for Black Sabbath named Geezer Butler supposedly had with the devil called Black Sabbath about the devil coming to earth and taking over the world. They made a trippy song called Planet Caravan that was one of the few space rock songs from the early 1970s and was later covered by the heavy metal group with Dimebag Darrell on guitar called Pantera.
My favorite song by Black Sabbath was Paranoid due to having what I think is the best riff that Tony Iommi ever did for a song by Black Sabbath. It is about a man who is paranoid that people around him are out to get him. When other people laugh, he cries because he thinks that the people are laughing at him. It’s a dark song like most of Black Sabbath’s death metal songs, but it is one of the most classic heavy metal songs from the 1970s.