Legal Systems
In general, region and society has their own legal system. Things get complicated however when multiple societies share an area — whether they interact directly or not. As there are multiple sentient races, each tends to have originally had it’s own legal system. However, as humans became the dominant force in an area, they tended to impose their own legal system, ignoring those of the other races. (Take a good look at gypsy/jewish legal systems at the end of the middle ages, and how they were subsumed for similar effects.) In the most part, this has been accepted, if not always liked.