Andervaan is rooted in history and noir film, but has several obvious fantastical elements. However these are things with which the overwhelming majority of the Andervaan population would have no contact or experience. So here are some ground rules when thinking about characters or NPCs...
If you want your character to have magic in Andervaan, understand it must be kept very discreet. Andervaan is a low-magic realm and most magic-users have to go through incredibly lengths to hide their ability from the government. Even separatists have little ability and the elves were so decimated in teh race wars, they have largely forgotten all magical knowledge.
The short of it is if you are making a character with magical ability in Andervaan, it might be best to consult with a GM as to how to make your character most feasible.
Psionics do not exist in Andervaan. And that's that.
If you wish to make a race other than human (be prepared for attempts on your characters life to be made on sight with this latter...), consult with a GM and get approval first. Bio-scanners are highly advanced and can be found at almost every twist and turn in all the cities. There are some ways around them, but they will require a bit of a crash course in the world setting.
Vampirism and Lycanthropy
There are no vampires in Andervaan. They simply do not exist in the world setting. Lycans are highly complicated for the aforementioned reasons in 'Races.' You will require GM approval.
Supernatural creatures and beings are present but incredibly rare in Andervaan. Mutant beasts are rumored to be found outside of the cities... but why the hell would anyone not out of their minds be there alone?