What's the demon training protocol? I don't think I ever heard of it.
Also called Beyond Failure training.
I had a good friend who was trying to go Pro who tried it.
This was early 00's.
Basically, warm up and load up to max sets in the 6-8 rep range of your max, and have your training partner help you go beyond failure for 10-12 reps.
The Smith Machine was DC's big-ticket item. So, if you failed completely, you just racked the weight. Lots of forced reps, high volume.
Great way to seriously overtrain or get hurt, even on grams of AAS like DC and his cronies.