There exist three dimensional planes, many believe it was only two, with the light, and the darkness.
This "something" in between...they cannot decide which to team with.
This dimension is known as Shadowren.
Every single creatures that lives...has an equivalent. But not in Shadowren.
Each Dimension has an owner. But we can cross that bridge once we get there.
Note
You can read the comics to understand this better...specifically issues 17-21.
However, it isn't required.
UPDATE
I think I'll work on this a year later. Sorry, but I just don't wanna write it anymore.