Vampires are the creation of the Unseelie or Dark Fae. They are a mix of human and Fae blood created in a fit of jealousy against the Seelie (some call it a stroke of brilliance). They were the very first creation and the Fae gave them quite a bit of power. As these creatures got older and more powerful, their dependence on the Unseelie grew less and less. These beings have the arrogance and charisma of the Fae.
Unlike the Fae, they have an aversion to Sunlight, an unforeseen consequence of pumping a human full of Fae blood. The skin became extremely sensitive and with no magic to protect them, the powerful rays of the sun can cause severe allergic reactions, including death to young vampires.
Evolution has given Vampires greater access to their brain matter and some of their powers are seen as magic. In reality, they are just the untapped potential of a mortal brain.
Vampires are extremely territorial and can become single-minded in their focus. They create clans for protections. It is likely that a Master Vampire is the head and has claim to all the other Vampires in their clan. There are also subclans called families. They can consist of actual family members, vampire and human alike but can also be other supernaturals and mortals that they’ve claimed.
As such, they follow semi-strict rules on inheritance as they are long-lived creatures. Different rules apply to different clans.
Vampires can be born or made. Because they share DNA structures with mortals, they have the ability to reproduce. But like all Unseelie creations, reproduction is not a given, so drinking a mortal to the point of death and then allowing them to drink from a vein will turn the mortal into a vampire.
The odds of reproducing increase if the partner is another vampire or human. It is extremely rare for a vampire to successfully reproduce with another supernatural, such as a Jinn or Mermaid.
There are no recorded cases of a vampire successfully mating with a Fae. The act of copulation would be repulsive to the Fae.
Age increases strength and power of will in Vampires. The oldest Vampires are called Masters.
The more they use their abilities, the stronger they become. A Vampire that has lived a long time can become immune to even their deadliest enemy, the sun. They can hide their nature more easily to other Supernatural creatures.