@Obscene Symphony - Basically the Vampire's Curse snowballed its way from a handful of deserving individuals. The story varies depending on who you ask but the main point is these progenitors passed it on through the ages via their descendants. You'd of been born a Dhampir thanks to an Alp or Draug knocking your mortal mother up, the same goes for your sire. All vampires start as Dhampir--it just means that the curse hasn't fully matured yet. Live long enough and curse worms into you little by little until one day you either tear out of your skin as a Draug, stare at a stranger in the mirror as an Alp or look down at your rotted remains as a Vetala. Dhampir are known as Sixth-House vampires (a hold over from before the Fourth and Fifth bloodlines withered away) and there are many sayings associated with it.

Potions will always kill you. Always. It's not even about overdosing. The changes they do to your body (read: intended effects) are fatally damaging. That doesn't really matter much to a vampire, since as long as it doesn't outright destroy the heart or head you'll just get up again. Younger, less powerful vampires often use them as a leg-up on their older and more experienced peers, since the only drawback worth mentioning is wraithburn. Unfortunately Wraithburn intensifies as one grows ever more ancient, leading the unwary into a life-shattering cycle of addiction.