When it comes to alignment, I think Lawful doesn't really mean "following 'good' society's law". It just means they adhere to their group's system or laws. A devout member of the Dark Brotherhood, would be a good example of Lawful Evil. Batman would be Neutral Good, as he acts outside of most laws other than his own, but not erratically and for the greater good. A Sith would usually be Neutral Evil, generally following suit as long as it favors him/her, but then turning on his/her master when the time is ripe. Nord Berserker could be Chaotic anything, goin' all out for his cause - or lack there of
. That's how I always understood it, I'd be glad to hear any other perspectives though, or corrections for that matter
Edit: clarification and a typo