Play with a vampyr (a.k.a, a vampire) among mortals. Be an immortal creature of darkness, develop blood powers and feed upon unsuspecting mortals. But beware that your nature remains a secret, for there will be no mercy if mortals find out what you really are.
To begin, choose the "Vampyr" trait in ruler designer. There is a minuscule chance that your character will be turned by one of the other 5 vampyr NPCs that are randomly placed on the map at game start, but do not count on that.