The legendary frontman Attila Csihar is known for works with Mayhem, but also several other bands. Of course Tormentor has the huge cult status. Here is the long interview with Attila himself
https://www.metal-rules.com/2020/01/01/attila-csihar-mayhem-tormentor/
https://www.metal-rules.com/2020/01/01/attila-csihar-mayhem-tormentor/