"Black Magick" is not really so much a description of a practice as a buzzword used by those who know very little about occult practice, or who do but enjoy giving themselves a dark aesthetic.
The black/white duality of magick falls away once you've begun to understand the nature of reality. What I think you are looking for is more what you'd call the lefthand path. This does not mean spooky dark evil stuff, more a system of study focusing on self empowerment.
The lefthand path is also where you'll find more focus on things I suspect your looking for... Curses.
You mention the three fold law, and accepting its consequences. That tells me you're looking for more karmic negative information. The three fold law is by no means a universally accepted part of occult magick. It's really a Wiccan thing that oversimplifies the concept of polarity and cause and effect. It's often disregarded entirely by left hand path practitioners.
If you'd like to learn more about specifically left hand path, don't start with demons and curses, learn first about magick and the occult. You need to transmute yourself into a being able to perform magick before you need to worry about cursing people or trying to make dark pacts.
Read good fundamentals books. Do research into learning the basics, try basic sigil magick, and especially above all else begin a meditation practice. Even a few minutes a day is a great start. One you've done some reading, and stepped foot onto this path, the answers you are looking for will find you.