This is Tom Platz, known as the Quadfather.
Other than the steroids, his method for turning into a veritable creature was very high rep sets of very heavy ass to grass high bar squats, and hack squats.
A hell of a lot of manga artists used 1960's strongmen and bodybuilders as references. Odds are you've actually seen his thighs in a manga somewhere.
Look at Midsommar's elder Björn Andrésen's influence on pretty boys in manga and anime too
Imagine a mixture of Assassination Classroom and Baki where Andre the Giant is a gentle shepherd who goes into berserker mode on the people trying to steal his sheep
