Rather than pursue a freak-of-the-month storyline, Steve Gerber immediately brings back the daddy issues. It’s really hard to write a compelling story about resisting Satan, especially when that story has already been told over and over, but he adds a cute little twist: It’s Daimon’s birthday, and his present is that his father inverts the pentagram on his chest.
The story is called Black Sabbath, so it looks like Gerber is studying Satanism.
Also, up to now Son of Satan only had his powers at night and by day he was a different personality occupying the same body, like Don Blake/Thor and Johnny Blaze/Ghost Rider. In this issue, he loses the weaker persona and becomes SoS full-time.