This picture was taken during DOOM development in 1993. Adrian's in his room (which he shared with Kevin Cloud)
and you can see here that he was modeling the Baron of Hell out of clay himself, based on his own sketch of the Baron.
Also, this was the very first clay model that was made for DOOM.
At this stage, he wasn't called the Baron of Hell, but rather, a Bruiser Brother (since there were two of them at the end
of the first episode of DOOM.