...I am making a post for the Edification of all on common vampiric traits.

The nice thing about the incredible diversity of vampires is that you can pick and choose all sorts of traits depending on the theme your story is going for. A common question asked about vampires is "do they reflect in mirrors? If they don't, is it only silver mirrors that don't show their image, or photography methods that don't use silver?" The answer depends, of course, on the vampire type being used, but the answer to this fairly simple question shows how these traits can tell you about the vampire in question.

For example, two common answers are "They do have reflections, except in silver mirrors because the purity of silver is deadly to vampires" and "they don't reflect at all- the undead have no souls, so they can't be captured in photographs or reflections." Though these have somewhat similar mechanical effects and use similar reasoning (something about the vampire is corrupted/missing/wrong), they result in a vastly different thematic energy.

A vampire that doesn't reflect in silver mirrors will go largely unnoticed, since most people don't use silvered mirrors anymore. This results in a message somewhere along the lines of "the Old Ways protected us from vampires, and discarding them has left us vulnerable to evil." Would-be vampire hunters might retrieve a mirror from their attic that belonged to a great-grandmother, literally reviving tradition to defend themselves.

On the other hand, our alternate scenario means that our modern technology is capable of quantifying evil and defending us from it. With our modern resources, we'll be able to sniff out the undead before they pose a threat. Our heroes might set up camera rigs or check people coming into a safe zone to see if they reflect. They'll probably also use other modern technology to defend against the undead threat. Altogether, this results in a vastly different story. Another story with different goals might decide that vampires do reflect, because their souls are either human or unquantifiable by something as mundane as a mirror.

Another question I get a lot is "Wait, silver? Isn't that a vulnerability that werewolves get?" Well, yes and no. Werewolves and vampires have often been intertwined in mythology. In one Eastern European account of a village supposedly threatened by vampires, one of the undead was said to "walk in the shape of a wolf". Dracula draws on these traditions with his command of animals, and some vampires even borrow the shapeshifting gambit entirely, covetous corpses that they are. Either way, the malevolence of these early legends meant that the supposedly pure-natured silver was used to combat them.

However, the legends eventually grew apart. Vampires often retained their aversion to silver, as their more subtle and social predation didn't conflict with the original symbology. It's only now, when authors seek to make vampires and werewolves more distinct from each other that vampires have lost that. However, werewolves got a lot burlier in their later forms. Expecting a cross or string of garlic to hold off a 300-pound slavering beast didn't make much sense to people, so they lost many vulnerabilities that couldn't be made more convincingly threatening. Silver was melted into bullets or onto daggers while fire was still employed to hold the beasts back, but garlic and holy water went out of fashion for our dear wolves.

Thanks for reading! If you have more questions about vampires, I may or may not have an answer– but I can promise you that I will have an opinion.