For this.. It would be good if you knew something of Moorcocks books, since he basically invented the Law-Chaos conflict.
Some basis about it can be found here:
http://en.wikipedia.org/wiki/Law_and_Chaos

But really, reading most of the Elric books should almost be a prerequisite for doing anything on Darke.
http://en.wikipedia.org/wiki/Elric

So much of Darke is, knowingly and unknowingly, based on Elric especially and Moorcock in general.