Ozzy Osbourne died at 76, weeks after his farewell show and five years after revealing his Parkinson’s diagnosis.

For 48 years, Des Rumney has been captivated by Ozzy and his heavy metal band Black Sabbath, rocking out to 90 concerts.

He became known as the Prince of Darkness and, relatedly, the godfather of heavy metal, which emerged as the name for the subgenre that flourished and then fractured in the wake of Black Sabbath’s su...