[@Blue Demon]

1 - No, you're perfectly allowed to avoid Ki/Arcane altogether, as well as body mods, if you prefer. Raw experience and skill go a long way if you've got enough of it.

2 - There's certainly room for something pertaining to demonlogy to exist. In theory, anything along the lines of actually summoning demons would not be explainable under the current understanding of arcane principals, but it would definitely be allowed, within reason of course.

3 - Not necessarily. You could play a civilian, a member of the CMAS, or a member of any given nation outside the Quadra powers. Anyone who leaves nation borders will likely be considered a 'Diver' by just about everyone, but your character doesn't need to accept the label, or consider themselves as such.