From my book and original site

Thanks mostly to the almost lost (no comment) movie Nosferatu Vampires have been seen as creatures which  
cannot survive in daylight and will be destroyed by the rays of sunlight. In many movies it is seen as light is 
good (pure) and dark is bad (evil) so light destroys darkness and those who dwell in it. It could also be said 
that it is  thought sunlight kills vampires is  because they are said to be the undead kept alive by fresh 
blood and sunlight  increases the rate of decay on human flesh. But that is a much more detailed discussion 
perhaps. Ever since  Nosferatu movies and shows have  insisted sunlight must kill vampire but not reanimated 
corpses (people call them zombies whether they are or not really) The original Dracula in the book  was not 
killed by sunlight but that changed when they made Nosferatu  (which comes from the greek word  
nosophoros which means plague carrier (Not Vampire). Supernatural Vampyre (Spirits, Gods, ect. 
Now let's compare that to the original) mythology in which they are  active at night but they were not 
generally considered vulnerable to sunlight. It has also been said and I agree that Vampyres are nocturnal 
creatures and it is easier for them to hunt humans for blood at night when most are tired it is harder for them 
to be seen and they often feed on humans as they sleep to not be noticed as easily. They are said to be 
stronger or more powerful at night. I believe Vampyres are not natural creatures but supernatural but very much 
living creatures. as sunlight makes most humans, other animals, and plants wake  up and have more energy during 
the day (energies the natural world ect) it depletes the Vampyre spirits energy  slightly as they are not from the 
natural world but another plane of existence (the shadow realms) originally which is in the shadows, darkness, and 
bothers there eyes. The Vampyres in human form) most spirits (not hosts) from other realms can only exist in the 
natural world usually for a certain period of time  (depending on there strength from feeding) unless they take over 
a body (possession) which is how a Vampyre human comes to be a Vampyre spirit enters a human unborn child 
before  they are alive (through either  reincarnation misplacement an astral sexual encounter ect) instead of a 
human soul (otherkin). These humans grow up normal however they may awaken to recognize they are a 
Vampyre (awakening) but most often can not believe in such a thing and must think the have human issues). 
Most of the Vampire community also believes there Vampyrism is a human condition  but this is my theory as 
well as many other Vampyres in the world. as we have a Vampyre spirit piloting the human vessel instead of a 
human soul we are controlled by the Vampyres need for more fuel as it is a stronger  entity in a human body 
so they need to to eat food as well as fuel the Vampyre. Being a Human Vampyrism it is more difficult to feed 
but often if they cannot be get food from a willing donor they well feed while they are asleep (astral) or the 
Vampyre will take left over energy when humans have more than they need or by letting it go through a 
glance giving them attention* or a touch (The Vampyres natural allure could help here). Vampyres can 
often barely stay healthy that way depending  on their environment so they may feed  on themselves 
out of habit and may get  sick. The human Vampyre often may drawn to the night and have  issues with 
sunlight but very rarely will  it be a major issue depending on how often they feed. It is not so easy  getting 
a willing donation of Blood or a  small bit of life force though most  other energy sources may work almost  as 
well. Human Vampyre in the community Vampyres are not permitted  to feed on an unwilling donor not to 
mention mail is never a good choice if  they know better and have integrity  but most in the Vampyre community 
do  if they drain an unwilling victim (which  is very rare) they are black listed from  the V.2. unlike in the 
supernatural  Vampyres the human Vampyre is  nothing to be worried about and  normally a rather very 
pleasant person (depending on moods and situations of  course lol). Not all Vampyres are big on community 
but a lot have come out of  the coffin (kidding) thanks to the  internet but many of us are worried  this may 
cause harm to our kin or ourselves so even more like to keep  quiet about what we are for it is very  likely 
they will be unfairly judged for  something we can't help being born this way...