Deadlands Preparation III

Ok, so now I have a shadow of a plot for three days, a shadow of a villain and a few cool scenes.
The next problem will be to make some of the things more concrete, including the location where things happen.
The first thing I will now work on, is the villain. He must be scary, after all, this is supposed to be a horror game, at least in parts.
The whole concept of a Deadlands adventure, at least for me is about the overcoming of real evil by the power of big guns. Victory however, must be paid for with humanity and morals, no one can stay a saint while fighting evil.
It is this dilemma between good versus evil on one side and cold rationality versus humanity on the other.
These four concepts form a carthesian grid of sorts, with the perfect neutral character at the null-point.
The goal of my villains is now to drag the players from that point into the extremes, giving them choices that lead them ever further from moral and psychological equilibrium and then confronting them with the consequences of their decisions.
Sounds grand and noble, right?
Well, the difficulty lies in breaking these ideas down into a cool adventure, so that the players have a lot of fun, blasting away at everything, right up to that point, where they realise what they have done and are scared of themselves.
I Think, I'll make use of dreams to drive some points home, but I won't go into more detail. Fleshing out the main villain will probably take some more time, I just wanted to get these ramblings out.
Oh, and there might in fact be a steamboat in the adventure. Thank Terry Pratchett for it.