Humans

Well. Humans. Though they lack the supernatural abilities of the other species, they also lack the drawbacks. This lack of drawbacks have allowed them to become leaders of the world. Maybe that's about to change with the introduction of vampires.
Humans come in two groups: Civilians and Hunters. Civilians make up the majority of the population. They are run-of-the-mill, average, everyday person. They have only found about vampires in the last decade or so.
Hunters have known about vampires and the other supernatural creatures for hundreds of years and are often the cause of the tension in the world. They threaten the peace with the vampires, but some have stepped back and allowed the alliance to form, though with a wary eye. They have more knowledge on supernatural creatures than any other species, due to ancient journals, encyclopaedias and stories passed down. There are very few old hunting families left still hunting, due to the high death rate, but many people have recently become hunters due to their suspicions of the vampires.

Vampires

Ah, the main attraction. Vampires are ancient. At least many of the surviving ones. Like the hunters, they have seen an upsurge in numbers as more and more people are turned. Most vampires are benevolent and live normal lives, with normal jobs, but some, especially the new ones, are arrogant and violent. The oldest vampires are in their 50 and 60 thousands, but many of the oldest ones have died or been killed. Older vampires are far more powerful than younger ones, but younger ones lack control, which can make them more dangerous.
Vampires are dead, though they can still preform most normal bodily functions due to drinking blood. They cannot age however, past the age they were turned at, whether that be 6 or 60. (Password part II: dead) All vampires are turned. They cannot be born, as no vampire can give birth or impregnate anyone. So no half vampires. The turning process is painful, unless vampire "blood" is drunk by the vampire being turned. To turn someone, a vampire must bite someone and then that person must die within the next day. If not, any chance of being a vampire passes. Then, the person must drink human blood within the next few hours or else they will die.
Vampires are stronger, faster and more durable than the average person. This does not mean they are invincible. They are vulnerable to silver knives or wooden stakes. If stabbed through the heart or head with either these, they will die. Cutting a vampire's head will do nothing though, unless done with a silver knife. They'll just be a disembodied head. Which sucks. They also cannot enter someone's house without permission, but once given permission, they can enter at any time. The exception is public places or building in which no one resides. Sunlight does not kill them, but it does cause their skin to feel like it is burning, as well as causing their eyes, suitable for seeing at night, to literally burn. Sometimes they can wear sunglasses to lessen the effecfs, but that isn't always effective. That being said, they can see clearly at night or in the darkness. Some vampires also have a unique ability (however, vampires cannot have shape-shifting as their unique ability). Primarily the older ones.

Witches

Witches are not known to the modern world, though strongly suspected. Witches are born, not made. The only form of magic that can be learned is the Dark Arts and black magic.
There are several hundred different witch covens, usually with very few members, around six to ten. Forming a new coven is difficult, as many witches are born into their covens. Each coven specialises in one area of magic, though they are well-versed in all types. There can be many witches covens in one area, as witches often work peacefully with one another. Witches are possibly the most peaceful of all species, with only a few warlike covens, and alliances with almost all species.
Witches however, often require sacrifices (usually animal) for certain rituals, though many have avoided this practice, unless totally necessary. Spells often take a while to cast, though charms are quicker but less effective. Some spells can take such a toll on them that it can kill them. Witchcraft also takes years to learn, about twenty-five years or so, so most fully-fledged witches are in their late thirties. They are one of the most secretive species, and put their own before anyone else. Witches can be both male and female. They are especially vulnerable to bronze, unlike the two other major species.

Werewolves

Possibly the most aggressive of all species, werewolves are living in secrecy like the witches. They have a long-standing grudge with the vampires, and many werewolves are also vampire hunters. Werewolves are primarily born, though a werewolf bite can lead to wolffish habits and superior strength to a normal human, though not to level of a supernatural species.
Similar to witches, werewolves live in packs, but there are far less of them and they are far bigger. A werewolf pack typically has upwards of thirty members, but are spread thinly of territories. (Password part III: here) Two may make an agreement to share a piece of land (usually cities), but they are typically territorial to the extreme. Also unlike witches, werewolves tend to have a hierarchy, with two to three alpha males and females leading the pack. Each pack's hierarchy is slightly different, though it usually has the alphas as the leaders and then the other werewolves fill the position of healers, hunters and warriors.
Werewolves are unusually strong and fast when in human form, though not inhumanly so. They can only turn into wolves at night, but not once a month. As a wolf, they regain control over their mind and thoughts, but everything becomes sharper and clearer. The downside is, as a wolf, they are more aggressive. They are unusually big as wolves as well superhumanly strong, fast and durable. Despite this, like vampires, they are vulnerable to silver. They are also much less durable than vampires and can die from certain diseases and old age.

Ghosts

Ghosts are, obviously, the spirits of those who have died. They are often a result of unfinished business, or dying too young and roam the Earth (or their area of choice) often becoming angry or upset as time goes on.
Only the most powerful ghosts can communicate verbally with humans, most need to use a witch, preferably a necromancer, as a vessel to talk. They can, however, interact with the objects around them, push things over, destroy objects and attack people. Some can make themselves visible to others. They are vulnerable to salt or steel, and while they can be banished from a house or area by certain incantations, the incantations can weaken over time and they can return. The only way to truly rid a house or area of a ghost is to finish their business for them, but due to necromancy being looked down upon by most witches, it is difficult to find someone to communicate with the ghosts.
Ghosts may haunt an area or a person and their power depends on how long they have been around. Newer ghosts are often in denial of their death and refuse to accept they are dead. The older ones have either become extremely angry or upset and immense emotion from a ghost can cause them to become more powerful.
Vampires and witches cannot become ghosts, but humans and werewolves can. Humans are most often the ones who become ghosts.