Fwacho said that a lot of things in The Way are based on early Christianity. A while ago I came across an article on a Christian website about "Outer Darkness" and remembered that Slade has an attack with this name. I don't remember this being discussed before so I just thought I would mention it.
I don't remember which site I originally read about this on, but it doesn't really matter.
http://en.wikipedia.org/wiki/Outer_darkness
Edit:
Does anyone know if "Inner Darkness" (Gaius has an unusable attack named this) has anything to do with Christianity? I searched some online Bibles for "Inner Darkness" and didn't find anything.