I had never heard of him. But there are lots of topics about the guy on Getbig from 2015 and earlier if you put him name in the search field. It seems Zyzz remained in the fitness news more after his death than Greg?
Both guys seem similar, the shouting, the extreme risk taking behaviour, ADHD manic depressive personalities. Inspirational or tiresome? But he definitely had a good physique
It seems Greg was on 250 fitness magazine covers, well made YT video: