Here is a link to my previous post on vampires. This post is not meant to re-hash all of the previous points, but rather to expand on certain areas.
Vampires as a Species
>>What nutrients do they receive from blood?
>>Did they evolve to get nutrients from any other sources as well?
>>>If so, why do they still drink blood?
>>How much blood do they need to consume per meal?
>>>Does their prey usually survive?
>>What happens when they don’t drink any blood?
>>>What are the first signs that they need to feed?
>>>>How long do these symptoms take to appear?
>>>>How do the symptoms progress?
>>>How long can a healthy adult vampire go without feeding before it starves?
>>What types of blood do vampires consume?
>>>>>What traits do they have that make them suited to hunt this type of prey?
>>>>Does the ABO blood type or Rh factor have any effect on whether the vampire can feed on any given human?
>>What are newborn vampires capable of doing, if anything?
>>At what age can vampires start to take care of themselves?
>>At what age do vampires typically start puberty?
>>What is the average lifespan (barring accidents or murder) of vampires?
>Appearance and genetic variation
>>What traits do all vampires have?
>>Which traits are variable among vampires?
>>If there are multiple vampire species, which traits are found exclusively in each species?
>>Here is an interesting five page article on the three species of vampire bats and how they differ to give you ideas.
>>Here is a link to my previous post on creating hereditary diseases.
>>Diseases that can be gained from the blood:
>>>Which types of blood are most high-risk?
>>>Here is a wiki article on vampire bats; under the Evolution section there is a list of problems that can arise from blood feeding (the anatomy and physiology section may also be useful for other traits vampires would have developed.)
>Scientifically speaking, if vampires are a species, they would not be able to breed with species that are not their own, however, since they mostly appear in fantasy novels, it’s fine as long as your story’s internal laws are consistent.
Vampirism as a Curse
>Here is a link to my previous post on creating curses.
>Who set the original curse?
>>Was it on a group of people or a single person?
>>How was the curse placed?
>>Are there any conditions which can be met to release the curse?
>>Can the curse be spread?
>>>>Can it only be spread to certain species, or just any in which the ritual to spread the curse can be completed?
>Do vampires need permission to enter people’s homes?
>>If so, do they also need permission to enter privately owned businesses or private properties?
>>Can they enter buildings that were previously someone’s home but have since been abandoned?
>>>If so, how long does the home need to be empty before one can enter it?
>>What happens if they try to enter one of these places without knowing that it is forbidden to them?
>Compulsion to hunt
>>Is this compulsion controllable?
>>Does the cursed individual know what’s happening?
>>Do they know when it will happen?
>>>Does it happen at regular times, or can they feel that it’s going to start soon?
>>>Can they prepare for it?
>>>Can they stop it?
>>Are there any specific targets they go after when they need to hunt?
>>Is this need more of a mindless frenzy or an obsessive, calculated stalking?
>Are there any other effects of the curse?
>>What are they?