Vampires Got No Change
Vampires are among the most studied, feared, and lusted after creatures of the natural planes. However, the word doesn't really do them justice, as there are so many kinds, each different from the next. A category like 'vampires' is as broad as a category like 'insectivores'; it tells one nothing about the individuals in it, except what they eat.
In some places, vampires are living, not undead, and they are merely exceptionally long-lived magical creatures. These vampires reproduce by birth, rather than selecting mortals to change.
Merely being bitten by a vampire can be sufficient to turn a mortal into one of the undead. This change can also be effected by a vampire draining the blood of a mortal to the point of the death of the mortal body, then resurrecting the victim by an infusion of vampiric blood.
Conversion in Death
Sometimes the method of death or the person's actions in life will be enough to ensure that their death is impermanent, and they return as a vampire. Suicides and those who have been killed by a vampire are considered to have died in such a way. Those who lived as heretics or traitors, or survived a vampire's bite, may also spontaneously change, in death. These changes generally occur in eastern Europe and Russia.
Post-mortem conversions begin with a corpse and don't require another vampire. These are usually cases of a dead person being buried without some sort of blessing, item, or ritual mutilation that would prevent vampirism. Commonly, scythes, coins, or crosses are added to the coffin, for this reason. Corpses may be cleaned with boiling water, bound hand and foot, beheaded, cut across the tendons, or buried head down, to prevent vampirism, and in some places, must be kept away from animals, lest one jump over the body and cause it to change. These changes are common to southern and eastern Europe, as well as to China.
In some cases, a victim, living or dead, may be possessed by a demon or other evil spirit, causing the individual to take on the culinary habits and traits of a vampire, while possessed. Unlike most other forms, this represents a reversible sort of vampirism, with the victim returning, usually, to the prior state upon removal of the invading entity.
(inherent passive bonuses, like strength and speed)
Not all vampires will exhibit signs of all the weaknesses listed. Some may not show any of the ones here, although we have tried to find those most commonly present. Vampires are affected by their weaknesses to different degrees based, at times, upon origin and age.
Like other undead, some vampires have an irresistible compulsion to count small objects in their paths. They are unable to proceed until the full number has been accounted for. In varying cultures, rice, poppy seeds, and millet have been used to impede the progress of such vampires.
While vampires will generally overcome a great deal of physical trauma, some are unable to recover from a beheading. In any case, if a vampire is unable to recover its head, it's going to have a rough time seeing things or biting them.
In places where Catholicism took a firm hold, vampires can be found who are vulnerable to exorcism, though these are likely vampires of the demon-possessed corpse variety.
Many vampires are not just vulnerable to fire, as their mortal relatives, but are actually flammable, due to changes in their tissues during conversion. A spare few, however, can combust upon contact with certain materials or when injured in certain ways.
Garlic has long been considered the bane of vampires, in the West, and some vampires may exhibit extreme reactions to it, from rashes to burns to anaphylaxis, which is much less severe for the undead, because they don't breathe.
Some vampires are victims to politesse, being unable to enter a home without an invitation. In more severe cases, the invitation must be offered by the homeowner, and the prohibition may extend even to public buildings. In less severe forms, even children and guests may invite the vampire in.
In Saxony, in particular, vampires have been found who react to lemons in much the way that vampires in nearby regions others are reported to react to garlic. This weakness seems to be contained to the region, or at least to lines that originated in the region.
The undead are frequently said to be soulless, and as such, they may be unable to reflect or cast shadows. While it seems to this researcher that such would be proof positive of incorporeality rather than soullessness, unless you want to say that inanimate objects possess souls, tradition holds that it is death that steals the shadow and the reflection from some vampires.
The power of belief and with it, the power of divine protection cannot be underestimated. Vampires with a mild weakness to divine symbols may be affected by a proxy, priest, or other servant of the deity wielding a symbol of the deity's power. Those with a strong weakness may be affected by symbols in the hands of even unbelievers. Reactions to holy water and an aversion to consecrated ground may also be seen in vampires with this weakness.
Water has long been held to be a symbol of purity, rinsing away filth and evil as it travels. It also separates the body from the soil and the power of the earth, possibly linking this to those vampires who cannot be without the earth of their grave. Either way, vampires with this weakness cannot cross running water, like rivers, streams, or irrigation ditches, but may be able to travel over relatively still water, like lakes, ponds, and non-circulating moats.
Although a weakness to silver is more common among European shapeshifters than vampires, it does still occur, at times. Silver may cause wounds that do not heal or even burns, to those with this weakness.
In the West, it is generally agreed that one of the best ways to kill a vampire is to drive a wooden stake through its heart. Oak, hawthorn, and ash are the most commonly suggested woods. Still, common though this is, not all vampires will die from it. Some may merely become comatose and others may handle it no differently from any other wound.
Sunlight is often attributed with a wide variety of detrimental effects on vampires, from inducing sleep or a coma all the way to burns, combustion, and explosion. While many vampires are photophobic, and with good reason, it is important to remember that not all of them suffer with a weakness to sunlight, and may find the daylight hours perfectly acceptable times to conduct business.
(active talents, like turning into a bat or controlling minds)