Vampires in the Buffyverse
One of the oldest fears humanity possesses must be the possibility of being buried alive, and until relatively recent history it was a very reasonable fear. Cases of premature burial abounded well into the 1800s, and the terror of waking up inside one's own grave must have been horrifying. Perhaps it was from these tragic and often fatal errors in believing someone was dead that spawned the idea of vampires: humans who were neither alive nor dead, but a strange combination of the two, static in terms of aging and malevolent and murderous towards humanity.
It's hard to believe Count Chocula and Count Von Count are even related to these guys, isn't it? The concept of vampires has changed greatly over the centuries, from the Eastern European version of dead men forced to carry their coffins on their heads and fight at crossroads to Bram Stoker's infamous Dracula with his penchant for turning into a wolf or becoming far too interested in pretty young damsels. Vampires have become deeply rooted into popular culture as symbols of the evil something that lurks in the darkness, sexuality at its most primal, and even the decay of human morality.
Each generation seems to have added a new layer to the mythology: the dark film "Nosferatu", the often campy horror flicks of the 1950s, the tortured television hero Barnabas Collins from "Dark Shadows" in the 60s, and a variety of other pop references. However, if one were to ask for the definitive source for vampire lore in the 1990s through the early 2000s, easily the most recognized would be the denizens of the television world Joss Whedon created in "Buffy the Vampire Slayer" and its spin-off "Angel", generally referred to together as the Buffyverse. This article will attempt to encompass some of the specific characteristics and personality attributes that occur in each series, serving to show how the traditional mythology has been embraced by another group of storytellers and their audience, as well as working as a guide for those who enjoy writing fanfiction based on the series, an activity Whedon has publicly supported on several occasions.
To begin, a vampire is a hybrid of human and demon. In the lore of the Buffyverse, the earth began as a demon paradise, and it was only later that humans eventually stole the land or managed to fight off the demons. One demon, however, did not depart for another dimension before it somehow mingled itself with a human, creating the first vampire. There are a variety of other demons present in the Buffyverse, but none of them are considered "pure." Vampires are not pure, either, and in the opinion of the Scourge, they are the most repellent of all demons due to their hybrid nature.
In the Buffyverse, a vampire is created when one vampire kills a human by biting them (usually on the throat, though this has never been specified as necessary) and draining them of their blood to close to the point of death, then forcing that human to drink some of the vampire's blood. Simply biting the person is not enough; the transferal of blood from the vampire must occur for the human to become a vampire. At this point, the human dies. The person remains dead for roughly 24 hours, then wakes up again as a vampire. While the new vampire has the memories, personality, and physical characteristics of the human it was, the major change that has occurred is that the person's soul is gone and has been replaced by a demon which will feed off the blood of other humans. However, a variety of other changes also occur, some of which will cause problems and opportunities for the fanfiction writer.
Demon v. Human Faces
Vampires have the capacity to appear human. They retain the same facial features and physical bodies that they had as human beings, though they are considerably paler than their former selves. However, they also have the ability to take on a second, demonic face at will. Some writers regard the human face as a mask and the demon face as a vampire's "real" face, while other state that the demonic features come forward only when needed. In this way, the demonic face could be likened to a cat's claws: out when necessary, velveted when unnecessary.
Vampires were almost always young, attractive people as humans, which can act as a lure to potential victims. The demonic face, on the other hand, is vastly different in appearance. Most of the make-up for vampires in the Buffyverse appears to be a combination of reptile and feline features. The eyes become very large and are usually gold in color. Facial ridges occur that extend the contours of the skull, creating bumps on the forehead and cheeks in particular. Teeth, obviously, become elongated and sharp, and it is the incisors that usually are given the largest change. Changes also seem to occur over the entire body when the face shifts, including a mottled coloring to the skin, an increase in the visibility of blue veins, and possibly increased muscle definition. Some writers have mentioned an elongation of fingernails into claws, but this has never been specifically seen on either series.
The shift from human to demon face is extremely rapid and takes less than a second in either direction. The vampire can wilfully make his or her face change, but at other times the change is brought about by moments of adrenaline surges. For example, violence will usually bring a demon face to the fore, as well as surprise, an instinctive defense mechanism, or sexual excitement, though vampires have also been seen in all of the circumstances with their human faces in place.
Vampires are much stronger than normal human beings, and they appear to become stronger with age. It is difficult to compare a vampire's strength to that of a Slayer's because, again, it appears that Slayers increase in power as they age. For example, Buffy in season 1 has trouble closing a door on a vampire without help, while in season 5 she is seen easily hoisting an iron hammer that the century-old vampire Spike cannot even lift. Likewise, Faith is often seen battling multiple vampires with relative ease in season 3, yet she is almost killed by the very-old vampire Kakistos.
Physical size seems to have little or no effect on the strength of a vampire. Though Darla may be much smaller than Angelus physically, she is also over 150 years older than he is and is quite capable of beating him in a fight. In the same way, the very physically slight Drusilla is able to carry Spike without any strain at all. The ability to carry heavy weights or perform physically demanding feats such as scaling walls and making long jumps is pretty much standard to any vampire, regardless of age, though again, the abilities seem to get better with age. In the final season of Angel, the dexterity and strength of both Angel and Spike are shown further than ever before in leaps of dozens of feet taken from standing positions.
Hand in hand with strength comes speed. Some vampires, such as the Master, are capable of moving so quickly that they seem to go faster than the eye can follow. While vampires in the Buffyverse are incapable of invisibility or teleportation (at least without spells), a few very powerful ones possess increased speed that can almost make it seem as though they appear out of thin air. However, it should be noted that the vast majority of vampires seen on either series tend to move quickly, but not with a level of speed worthy of, say, Superman. They can't run so fast around the earth that it starts turning backwards. No speeding bullet situations should occur.
Increased Sensory Perception
Like other predators, vampires have very sharp eyesight, and their night vision is extremely good. However, there is no reason to believe they could see in an environment completely devoid of light, and their vision does not extend to x-ray vision, microscopic levels of vision, or heat vision. They do, however, have the trained predator's ability to notice small details.
Vampires have hearing sensitive enough to hear human breathing and heartbeats. Oddly enough, however, the sense of hearing does not appear to cause an increased sensitivity to loud noises. Spike enjoys blaring music loudly without any sign of pain, for example. There are, of course, limitations to the believability of sharpened hearing with Buffyverse vampires. They would not, for example, be capable of hearing a heartbeat through concrete, and a vampire could not have found Angel under the ocean simply by listening for him. Also, remember that there are a lot of noises going on at any particular time, and training the ears on just one sound could be difficult in a noisy environment.
The vampire's sense of smell has probably been played with more than any other sense in fanfiction. What is canonically known is that vampires do have the ability to use smell more acutely than humans do. Again, like sight, the sense of smell in a vampire would be similar to that of a predatory animal. They probably can scent humans, and they may very well be able to tell individual humans apart by scent. However, there's no reason to assume that vampires would be capable of picking up scents to the extreme that we see happen with Oz where he is able to determine Willow's location inside a building and her emotional state with a couple small sniffs from inside a van.
Here, senses seem to veer in the opposite direction of humans. Angel states on several occasions that his sense of taste is dulled. Spike enjoys human food, but most of the food we've seen him eat is either very spicy or crunchy, both of which are actually tactile sensations instead of actual tastes. As for different kinds of blood possessing different tastes, this isn't backed up in canon very well. The one exception to this is Angelus and the Sunnydale swim team. He did find the taste of their blood disgusting because they had been taking drugs. However, it was not the blood that had a specific taste to it, but rather the drugs that did. There's no reason to assume virgins, witches, powerful people, the young, the old, men, or women have a specific flavor to their blood, though it's possible disease or medication could effect the taste of it. On the other hand, the concept of vampires being able to detect changes in the taste of person's blood is practically canon in fanfiction.
This is a tricky one in the Buffyverse. On one hand, vampires seem to be very tactile creatures, but on the other they have a massively increased tolerance for pain, which suggests that perhaps their sense of touch is deadened a bit, rather like the sense of taste. There technically aren't any canon statements regarding a vampire's tactile sensations as being more sensitive than a human's, though usually fanfiction increases the pleasurable sensations of touch, particularly in regards to sexuality.
Vampires do not age in the same way as humans. They appear to freeze for an extended period of time at the exact age when they died. Centuries will usually pass without any significant change occurring for the vampire in terms of facial features (a challenge for actors who in some cases played the same role for up to eight years). Physical changes do, however, occur. Both hair and nails continue to grow. This is actually a change from original statements about the series. Whedon at one point told his actors that vampire hair does not grow, but Spike's hair had clearly grown a lot between seasons 6 and 7, and flashbacks of Angel, Darla, and Drusilla all show hair growth clearly, as well as the possibility of facial hair, though Angelus's moustache looks so laughable it actually could be a fake, and crazy-basement Spike appears not to have any stubble.
Eventually, however, age apparently catches up with vampires and they "move past the curse of human features." Usually this seems to happen only to vampires who have achieved extremely long lives, perhaps over a thousand years. The characteristics appear to include an extreme pallor to the skin, hair loss, a permanent demon face without the option of a human mask, and cloven feet. On the positive side, however, strength and power increase with age, and they become proportionally more difficult to kill, Kakistos having to be staked with something roughly the size of a telephone pole and the Master actually impaled. Oddly, some older vampires, such as the Master, appear to leave remains rather than simply turning to dust.
As stated earlier, vampires do not traditionally have souls. There is, however, some controversy over exactly what a soul is in the Buffyverse. Remembering that Joss Whedon is, depending upon which source one reads and how different quotes are taken, either agnostic or atheist, the religious implications of a soul do not necessarily come into play in the Buffyverse. It is, of course, entirely possible for an atheist to create an imaginary world that is theistic, and the religious ramifications of several aspects of the Buffyverse could easily fill many, many pages, but traditional definitions of the soul don't necessarily come into play here. For want of a better definition, a soul seems to be the desire to do what is morally right on the grounds that one should try to do right rather than wrong. Granted, many human beings would then have no souls by this definition, but defining a soul as a conscience seems to be the best we can do.
There are, however, at least two exceptions to the rule of vampires being soulless. Angel is the first, having been cursed with a soul as punishment for killing a young Gypsy girl so he could experience guilt as a penalty, and Spike is the second, having regained his soul after a series of trials with an African wizard/demon in an attempt to make Buffy consider loving him. Another possible exception seems to be Darla when she is very far along in her pregnancy with Connor. She appears to be experiencing a soul vicariously through her human child, and this is what allows her to perform the selfless act of killing herself so Connor can live. Another possible exception is Lawson, the vampire Angel sires in a submarine during the Second World War. Angel had a soul at this time and killed Lawson only because the human was about to die and was also the only one aboard the submarine capable of piloting it. Lawson seems to have experienced only a partial removal of his soul; he's evil, but he doesn't seem to enjoy it very much. It's also intriguing to consider the possibility there may have been other vampires with souls. It doesn't seem likely that there is spell to ensoul a vampire and several Orbs of Thessula, whose apparent only use is in putting souls back in vampires, and that Angel was the only one stuck with a soul.
The ramifications of not having a soul are complex. Vampires seem to have the ability to tell the difference between right and wrong. The one possible exception here is Drusilla, who appears to be so insane that she could easily be considered incompetent. However, vampires, though capable of comprehending morality, don't particularly care about good and evil, and when given a choice, tend to choose evil because it's usually the easiest and, to a vampire, most fun option. A vampire's default choice will usually be violence. In this way, they are the ultimate manifestation of the human id, with no ego constricting its desires. Additionally, human beings are not considered as important as vampires to them; in the same way that predators don't really feel pity for prey, vampires do not consider human feelings, except perhaps to relish in a chase or, in the case of Angelus, consider a kill to be some sort of warped artistic achievement.
While it seems logical to assume that any living (or pseudo-living) thing would act to protect itself, it bears repeating that this is generally the case with vampires as well. They do, however, seem to enjoy taking risks: provoking mobs in the case of Darla, Angelus, and Spike, as well as Spike's penchant for tracking down Slayers. They seem to like the adrenaline rush of adventure, perhaps a way of breaking up what essentially must be a relatively repetitive life that goes on endlessly. Also, vampires will usually put their own interests ahead of anyone else's, such as Darla ditching Angelus in France to Holtz's none-too-tender mercies in an attempt to save her own bacon.
However, there are several instances when vampires will put themselves at physical risk. Minions will almost always obey the vampires who rule them, even if to do so is essentially suicide. They seem to have no problem with being essentially cannon fodder. For example, the Master orders the Three executed by Darla. When the first one is killed, the other two appear to offer no resistance at all to being killed. This usually ties into a sense of honor, particularly if the vampire has failed in something and considers death a proper penalty.
In other cases, vampires will risk their lives for other vampires due to emotional attachment. We have seen this happen with Darla and Angelus, Spike and Drusilla, and William and Elizabeth. Drusilla even goes so far as to protect Angelus against Spike. What is strange is it is difficult to construe most of these acts as anything other than selfless. Darla's rescue of Angelus from monks in Rome may have been a bit of a lark on her part, but she does put herself at risk to do it. Spike repeatedly risks his life for the sake of Drusilla. William commits suicide due to Elizabeth's death in an effort at vengeance. This suggests that sometimes the emotional drives of some vampires are not as simplistic as they may at first appear.
In the cases of Spike and Darla, we actually have vampires willing to forego self-preservation in the interest of specific humans. Spike allows himself to be tortured in season 5 to protect both Buffy and Dawn, while Darla, as previously stated, kills herself so Connor can be born. There is the suggestion Darla is acting under the influence of a borrowed soul in her case, and Spike later choosing to die to close the Hellmouth occurs after he has a soul. Angel, of course, repeatedly risks his life for humans throughout the run of both shows so long as he has a soul present. Generally speaking, though, these are exceptions that prove the rule. Vampires do not generally risk themselves for human beings.
In season 5, Buffy bluntly states that vampires cannot love because they do not have souls, only to be immediately corrected by Drusilla. Granted, Drusilla is completely insane, but she seems to have a point.
Vampires usually do not have much feeling for human beings. They are essentially viewed as food by the majority of vampires. However, very occasionally, some signs of liking a human may occur. Certainly Angel cares deeply for the humans in his group, though again, this is only when he is in possession of a soul. Spike also cares for humans when he has a soul, though he proves to have a more complex relationship with the concept of liking humanity. At different times, Spike shows some degree of amiability towards Dawn, Joyce, Willow, Tara, Buffy, and perhaps even Giles when he is not yet in possession of a soul. He also prefers a world with human beings to one without humans and with infinite vampire control. Darla also seems to be at least nominally fond of Lindsey, while Drusilla "likes" Lilah because of the darkness in her. Again, these are exceptional cases, but they do show that some vampires are capable of forming some level of emotional bond with a human.
When it comes to other vampires, an entire gamut of emotional attachments is possible. Vampires can detest and even kill one another, particularly over territory and power, as seen with Spike and the Anointed. They can also form close relationships, up to and including love. It is interesting to note that in at least two cases, Elizabeth and James and Drusilla and Spike, these relationships last without significant interruptions for over 100 years, no small accomplishment when compared to the current human divorce rate of 50% in a far shorter time. As for the possibility of homosexual relationships between vampires, there's nothing to suggest that vampires are exclusively heterosexual, or exclusively anything, really.
Vampires in the Buffyverse do have some dealings with non-vampire demons. The reactions to different kinds of demons vary widely. We don't have any canon examples of vampires specifically feeding off any non-human species (bagged pig and otter blood doesn't really count) other than other vampires, and even that is rare. It could even be that vampires can't digest demon blood. They can, of course, kill them without feeding from them, and in some cases could do this for sport. On the other hand, vampire/demon friendships are possible, as seen with Clem and Spike, and working relationships seem relatively common since vampires will hire some demons to do tasks they don't want to do themselves or to act as extra muscle. There are other demons who strongly dislike vampires and vice versa, as is the case with the Scourge, and certainly there are demons much stronger than vampires that they would want to avoid if possible.
Limitations on Vampires and Ways Around Them
Even in the Buffyverse, vampires have their limits. In the original film version, for example, vampires were capable of flight, yet never had this trait in the television series (partly, I suspect, due to budget constraints, and partly because it did look rather silly). However, most limitations vampires have can be gotten around by a determined writer.
Vampires cannot stand in sunlight without catching fire. This rule actually seems to be a very traditional one, suggesting the sun is equated with goodness and that vampires cannot therefore withstand its influence without harm. In the Buffyverse, it's possible for a vampire to realize he or she is on fire and, if possible, get out of the sunlight in enough time to keep from burning up. It's not a case of instant immolation.
There are a variety of ways of getting around the sunlight problem. One is simply to keep the setting of most vampire scenes at night. This can prove difficult, though, in time periods prior to electricity since there generally wasn't a great deal going on at night in those days, and the number of people they can interact with would be substantially smaller. Another option is to set scenes indoors. As long vampires are not in direct sunlight, they should be fine. Do not, however, have them standing next to a window unless, as was introduced in Angel season 5, it happens to have necro-tempered glass. Spike and Drusilla also circumvented this problem by spray painting the windshield of their car black and navigating through quite a small patch of clear glass. Subway systems, sewer tunnels, caves, mine shafts, and any other underground situations that negate daylight can also be used as options, though again, there needs to be some way to light them. Spike has also used blankets and other heavy-woven items to get around in daylight, albeit with quite a bit of smoking, even in the middle of the desert.
Two other options have been shown for getting around the problem of daylight sensitivity. One is the Gem of Amarra. Introduced in "The Harsh Light of Day," this ring was able to protect vampires not only from sunlight but from staking. It existed for several centuries prior to this, but had been lost for a long time. However, it was later destroyed by Angel, and as it was the only one, no fics set after "In the Dark" can logically use it. The other option is alternate dimensions. In Pylea, Angel had no difficulty with sunlight, and was even able to see his reflection. There could be other dimensions where this is possible as well.
One final note: Turok-Hans seems to have an immunity to sunlight, along with an ability to enter homes without an invitation. This could be on account of their extreme age, but no other vampires, even Kakistos or the Master, showed an immunity to sunlight based on age.
For a staking to work, the stake must be made of wood and it must penetrate the vampire's heart. This can be done either through the chest or through the back. The wood does not have to be particularly strong; we have seen pencils successfully kill vampires. This suggests that maybe vampires don't have particularly strong breastbones. However, aim needs to be perfect. If the stake misses the heart, the vampire will not "dust." In cases of extremely old vampires, a very large stake needs to be used, as stated above in the examples of Kakistos and the Master. There are ways around even dusting, though. Darla, after all, was staked to death, but she was able to come back due to a spell done by Wolfram & Hart. This does appear to be extremely rare, though.
As is the case with most living things, a vampire doesn't live if its head isn't attached (apologies to Lorne). The trick here is that one has to get close enough to behead the vampire. It's possible to kill a vampire from a distance with a crossbow bolt if the aim is accurate, but it's generally a lot more difficult to behead something from a distance, Buffy's cymbal-throwing being a notable exception. Guillotining, however, would work fine, as would most very sharp blades with enough strength behind them, including axes. As before with Darla's case, reanimation via spell is a very remote possibility.
Closely related to sunlight, fire in general can kill a vampire in the Buffyverse. Vampires can use candles, sit near open flames, heck, they can toast marshmallows if they want to. What they can't do is allow themselves to catch fire. Vampires appear to be more flammable than human beings. As is the case with most fire, if it's put out quickly, the vampire won't die. In other words, unless the vampire has been doused in kerosene or alcohol, a quick stop, drop, and roll will probably fix the problem.
This is one of the most contentious areas of the Buffyverse. Vampires suffer burns if they touch blessed objects, and they are repelled by them on sight. The tricky thing is that in the Buffyverse, those objects have been also exclusively Christian. Again, as above, Joss Whedon is apparently atheist, so this is an unusual situation. In "The Wish," the vampire version of Willow is repelled by a cross, yet Willow as a human was Jewish. Additionally, it is ridiculous to assume that every vampire who is affected by a cross over the course of both series was in life a practicing Christian.
This leaves two possibilities. One is that religious articles from all faiths have an effect on all vampires. This would suggest the efficacy of the object depends neither on the faith of the vampire's human self, nor the faith of the person holding the object (Willow often uses a cross to repel vampires as a human, and there is no reason to assume all the Scoobies are Christian either), but rather on the belief of people somewhere that the object is holy. This would actually be in line with the usual situation on the series that magic can effect those who don't believe in it, even accidentally doing or saying something that causes something to occur, because belief in the spell exists somewhere in history. The episode "Fear Itself" with its accidental summoning of the fear demon is a good example of this. There was no need to believe in the spell; it existed since someone believed it would work. The only other option possible that I can discern would be both series openly supporting Christianity as the only religion capable of creating holy objects. This really doesn't feel like it fits with the rest of the series, which includes a cosmology that has Powers That Be and includes both Angel and Oz seeking out Buddhist monks for help with difficult problems as well as Tara and Willow's devotion to a variation of Wicca.
As for religious articles that have been seen being useful against vampires, the list includes crosses, holy water (though not regular water, as First Drusilla apparently was bizarrely using on Spike in season 7), and in one case communion wafers were seen in Buffy's weapons chest, though these were never used on the series. It's possible that the sword the Boxer Rebellion era Slayer uses to split Spike's eyebrow, leaving a permanent scar, was also blessed, which made the scar permanent. Holy water is by far the most versatile of the holy objects since it can be used at a distance. It is also interesting to note that Angel showed extreme apprehension going into a Catholic church in season 1 of Angel, yet Angelus had no problems actually killing a priest in a confessional in 1860. This suggests it may have been guilt rather than specifically a physical reaction in Angel.
Garlic actually also belongs under the list of holy objects as it was considered a blessed plant capable of repelling demons, particularly in Eastern Europe well into the 1800s and possibly even later in some areas. However, it appears to have been used only once in the series, when Buffy is trying to prevent herself from going to Spike's crypt in season 6. It's unclear how hanging dozens of strings of garlic in her windows is meant to do this. It could be that it repels vampires in the same way a cross would, that it creates a barrier like that found around a home, or it could detract from the desire to want to go to Spike in the first place, therefore acting as a kind of self-cleansing rather than something directed at Spike specifically. Various fanfics have had garlic create a burning sensation if a vampire accidentally eats it or even feeds off a person who recently ate garlic, but this last one seems a bit much.
The concept of invisible barriers around buildings which make it impossible for a vampire to enter has changed over the series. Originally, Angel suggested he needed the written invitation of "enter all ye seeking knowledge" written on the school in order to enter it, yet this seems completely nullified in short order, with the barrier being restricted to dwellings only. For a vampire to enter a residence, it must be invited in.
There are several ways around the barrier problem. The first and easiest is to be invited in by one of the residents of the home. What constitutes an invitation is sketchy. Certainly, a verbal, "I'm inviting you in" is sufficient, but the idea can be drawn out to the point of a welcome mat providing permission. Additionally, what constitutes a resident can be confusing. Obviously, the owner of a home could grant permission, but a visitor could not. Family members living in the house would work, as was the case for Dawn or Liam's sister Kathy. Servants are more ambiguous. If they live in the house, maybe they could invite in a vampire. If they live in an outbuilding on the same estate, then probably not. If the person is not free, such as a prisoner in a jail cell or a slave, there is some question whether they would have enough authority over the area to permit entrance since they technically have no share in the ownership of it. Also, what constitutes a dwelling? Houses, apartments, condos, trailers, and houseboats all seem logical, but could a homeless person living in a cardboard box possess a barrier around the box? What if he legally owned the box since he had purchased whatever came in it originally? At what point does the barrier come into effect?
This is also only the case for humans, not demons. Demons of any kind do not have a barrier around their homes. This brings up the question of whether Doyle's apartment would have had a barrier since he was half demon, and whether Cordy's home would have had a barrier when she became a demon. Once the human owner is dead, the barrier immediately disappears. As to what would happen if, say, a human died, the barrier dropped, a vampire entered, and then the human were given CPR and came back, I have absolutely no idea. It's even possible the vampire would wind up trapped inside the dwelling if the barrier went back up, or maybe the vampire would die, or perhaps he or she would simply be thrown out of the place by an irresistible force.
Of course, there are plenty of other ways to deal with barriers. Vampires can't enter the house, but bullets, Molotov cocktails, flaming torches, tear gas canisters, wild dogs, demons under a vampire's employ, or anything else can. The house can be set on fire. At what point the house would be so burned up it would cease to be a house and the barrier would fall is another question. There is also the possibility of bribery via hostage, as Spike once told Dawn in one of his ghastly little fairytales in season 5. Starving the people out, messing with utilities, wrecking balls, all of them are possibilities.
Turok-hans, as noted before, don't have any problem with barriers. They just blast right on through them, possibly because they are very old and powerful, or maybe just because they look amazingly like Uruk-Hai, but a lot of rules don't hold true for them, and they can almost be considered a completely different breed of demon from regular vampires.
We have only two documented cases of a vampire getting sick. One is Drusilla. She is wasting away in season 2 of BtVS for some unknown reason that apparently has something to do with an "idiot mob" in Prague. For a full examination of the ramifications of Drusilla's illness, see "Drusilla's Mysterious Malady." The other instance is when Angel is infected with Killer of the Dead by Faith via a crossbow bolt. Aside from these two instances, I am unaware of any other illnesses contracted by vampires in either series. However, as both of these illnesses had cures available, though Drusilla's may have been a more general cure for any sick demon, it's possible other vampires contracted them at some point or could contract them in the future.
Inability to Procreate Sexually
Vampires can't have baby vampires. Actually vampires, by their status as technically dead things, shouldn't be able to do a lot of things, including have sex, heal their wounds, eat regular food, digest, speak, stand, walk, think, or exist. This is a fictional universe, so you have to draw a line somewhere in there, though, or it simply ceases to work at all. For the Buffyverse, the general rule is that what is dead cannot create life.
The big honking exception to this rule is Darla, who becomes pregnant with Connor by Angel. Two vampires should not be able to have a human child to begin with, but this is chalked up to the life Angel is owed from when he underwent the trials for Darla only to find out that her life could not be saved due to a technicality. Obviously, this isn't going to come up much in fanfiction in any other circumstance unless there is a dang good reason why a vampire is able to either become or get someone else pregnant. Shanshuing Angel or Spike, obviously, negates the problem since they would then be human with all the accompanying physical abilities and limitations.
Limits to Physical Healing
Vampires can heal from most wounds very quickly, much more quickly than a human, and possibly faster than a Slayer. Broken bones, massive burns, cuts, scrapes, concussions, you name it, it can probably be fixed. Some wounds obviously take longer to heal than others. Drusilla was still visibly very scarred from Angel's dousing her and Darla with gasoline and setting her on fire over a week later. Spike was in very rough shape after Buffy's beating in "Dead Things" well over a week later as well, and it's logical to assume his torture session with Glory left him very sore for quite a while. Skin doesn't knit back together so fast you can see it moving on a vampire, though. It's not that quick. But it's still fast.
There are, however, things that simply won't heal. Hacked off limbs will not grow back, as seen by the vampire Buffy nicknamed Fork Guy in "Teacher's Pet." This would presumably go for eyes as well. Burst eardrums are another matter, and might go either way. Spike's scar he received in 1900 is still present, usually explained in fandom as the blade used being somehow special, though canonically this is never stated, and burns received by all other religious objects seem to eventually fade away. Tattoos, however, might be explained in the same way as Spike's scar if somehow a blessed needle or ink were used, perhaps by being dipped in holy water. Angel's tattoo for example, which necessarily would have to have been done after his turning since it is a letter A and his human name was Liam (unless his last name began with an A), did not heal over.
It goes without saying that injuries that would kill a person might not kill a vampire. Things like being soldered into a box and dropped in the ocean or having a pipe organ fall on a vampire are nasty and will cause a vampire a good, long recuperative period, but they'll survive if they aren't staked, burned up, or beheaded, generally speaking. At one point in "In the Dark," Angel's friends worry that he has been so badly tortured that he needs to be taken to the hospital, but Angel refuses and is able to survive without medical aid.
Also, it seems that some physical problems a person had prior to their becoming a vampire will not be healed. Drusilla does not regain her sanity when she becomes a vampire, Dalton still needs glasses, and Darla is apparently still carrying around syphilis. Oddly, Spike doesn't seem to need glasses anymore, though.
Vampires don't have reflections. The old theory on this was that a person's reflection was actually their soul; hence a vampire would have no reflection since it had not soul. This doesn't hold true in the Buffyverse, though, or Angel and later Spike would have been able to see themselves in mirrors. This limitation must have created a technical nightmare for production on both shows, causing trouble with glass, metal, flooring, anything with a polish on it, and sharp-eyed viewers can sometimes catch accidental vampire reflections in various surfaces. Happily, this isn't a problem in fanfiction.
As stated before, Angel could see his reflection on Pylea, and it's logical to assume that there could be other dimensions where vampires have reflections as well. An enchanted mirror or a spell to create a reflection isn't far-fetched either, but it would need explanation.
This leads to a related topic. Why wouldn't the vampire's clothes at least reflect? For that matter, where do the clothes go when the vampire turns to dust? The answer is simple. I have no idea. Just roll with it.
The concept of vampires in the Buffyverse is very complicated, and there are loopholes with yet more loopholes (like a vampire cursed with a soul unless he's not anymore). Individual cases will vary. That's what keeps the vampires in both series interesting and fresh instead of stagnating in baddy-of-the-week roles. Harmony's ability to essentially go vegetarian is an aberration to the rules, but it's a fun one to play with. Lawson is an unknown quantity. Angel is so confused about who he is that he doesn't know what's up and down most days. If you can successfully get inside Drusilla's head for any length of time, worry.
Whedon's universes have fluid rules. This is why we have canonical AU's like the Birthday-verse, the Wish-verse, the Asylum-verse, and Pylea. Fanfiction has even popularized the all-human AU, where vampires don't exist, but then writers need to deal with traditionally vampire characters experiencing the entire range of human problems like age, illness, and actually being able to see bad hair days. Realize too that if you are playing with a "what if" situation that begins in canon and then diverges down another road, different ramifications will probably occur for the characters, and that needs to be taken into account as well.
The main point of all this is simple. The Buffyverse has rules that need to be followed when it comes to vampires. If you want to circumvent those rules, there are ways of doing it, but you need to explain how and why things are happening the way they are in the story because it's going to confuse people familiar with the rules as they stand. Let's face it. No fanfic writer is in this to make money. We're in it because we enjoy it. This is like the neighborhood that gets together and plays stickball. You're probably not expected to follow the rules as closely as if it were the World Series, but if you suddenly start running the bases backwards, people are going to go "Hey! Don't you know how to play the game right?!?" Joss's game might be a little complicated, but it's also a whole lot of fun.