Here's the final illustration!
And now let me take you through the process!
I ended up starting this one out on a mid-tone background. I was originally going to just doodle them, and a few of these were even sketchier, but I didn't save those layers.
And then I cleaned some of them up a bit.
I colored/shaded them in, and moved the characters in the BG back a bit, so that they looked more distant.
I set the BG lines to be a lot more opaque so they don't look as jarring.
And then I blurred certain elements of the characters a little, so important parts were more focused.
I blurred my characters with motion blur!
Don't worry the next step fixes the spookiness.
I set the foreground to 75% opacity and Vivid Light. And then the background blur was set to 58% opacity and Overlay.
I decided I wanted that attack to look more epic. So I drew some action lines to create a better focal point.
I set the object to Divide, so it would fit in better.
I decided that wasn't enough of an effect, so I duplicated it and rotated it slightly so there would be two of those. I also set this to Screen 42%.
Then I duplicated that one again and set the new effect to Lighten 55%.
And then the final product! I just added some noise effects to give it a little more texture.