“ In a society, people who are in a higher postition of authority have a bigger incentive to stay on the right side of the law since the more authority you have, the punishments for criminal activities become much more severe. To the point where the most powerful face defacto death/life sentences for every crime.”
“ It is possible to buy magical abilities. The process is very dangerous though, involving chemicals, rituals and surgery possibly leaving the aspiring mage insane, retarded or scarred for life.”
“ When you sleep, your soul briefly returns to the place where it was created/goes to when it dies, and seeks nourishment. Everybody's soul is created with a little link (or you could say a greater entity calls it back) to that place so that it can return easily, but upon death, the soul returns via that and annihilates the link as if returns.
Also, as an added thingy, you could say the entity supplying the link, or residue of the links themselves, (whichever) is the source of all arcane power.”