Ozzy Osbourne filed to trademark Prince of Darkness before death Ozzy Osbourne filed paperwork to trademark his Prince of Darkness nickname in the US before he died last month. 5 August 2025 Ozzy Osbourne tried to trademark his Prince of Darkness nickname before he died. Ozzy Osbourne filed to trademark Prince of Darkness before death The 76-year-old rocker passed away at his home in England on July 22, just weeks after his final Black Sabbath gig, and he filed documents to trademark his nickname on June 13.