I love dark games
Yes I have ran into the "glowing" effect before, and always
comes down to a shader.
There are several things you could try. As I stated before, you
could spawn your characters when getting closer, lower the alpha
so they are transparent until you approach, or switch shaders.
You said you tried many shaders, just which ones? Also look
into COZ (creator of zombies) shaders. He made several that
give a nice effect without the "glow".
best
edit: found this old thread on shaders, should be of help to you.
Read thru it, but remember some of these shaders may no longer
work?
http://forum.thegamecreators.com/?m=forum_view&t=155573&b=21
You know you're a bad gamer when you're able to run out of infinite lives.