There are many unexplained phenomena in the world, one of the most prevelent is people developing unusual abilities.
Perfectly ordinary children may be born with the ability to communicate with ghosts, walk through time or many other varied gifts. Sometimes these abilities manifest shortly after birth, other times not until puberty.
The abilities have little pattern to them but it has been noticed that genetic relations seems to play at least some part, having a parent or grand parent with a supernatural gift markedly increases the likelyhood of a child having it, although the chances are still incredibly low.
Supernatural creatures also often acquire a variety of paranormal abilies as they develop. This is much more common than humans developing them, particularly with associated gifts.
Prolonged exposure to the gate seems to increase the chances for developing a paranormal gift as well. Overall the development of each supernatural creature is distinct, while several core traits usually stay the same they then branch off into many distinct developments. In the case of vampires and werewolves the one who turned the person usually has an impact on their development.
Humans who possess some paranormal gift are also more likely to develop others, although it's unclear if this is natural or because of their greater exposure to other supernatural elements caused by the pre-existing gift.
Certain abilities can cause concern or hostility amongst others, werewolves who develop common vampire abilities are often thought poorly of amongst their group and humans with paranormal gifts are often mistrusted by normal humans or The Temple.
Supernaturals who develop similar abilities and traits often tend to cluster, either simply because of their commonality or because of a belief that they are similar for a reason, sharing a bloodline or being blessed by a particular spirit etc.