The Bell, Book and Pistol universe is an alternate reality universe where Magic and Science were developed simultaneously. This is due largely to the efforts of Professor Nicholas Flamel, the creator of the Philosopher's Stone. Magic existed before his time, however he was the first one to begin studying Magic and the way it worked in a systematic methodology so that how magic works could become understood. The story of the Web Comic is set in modern day San Francisco.
In the Bell, Book and Pistol universe, one's Flamel Index is the measurement of one's inborn power. One's Flamel Index does not chage from birth. If one's Flamel Index is too low (below 376), one is unable to wield magic of any kind. The closer one's Flamel Index is to 500, the more powerful one is at various types of magic.
There are a select few who have Flamel Indexes above 500. The most notable instances are the Councilors of the International Council of Magic, Nicholas Flamel himself, and Nicholas' wife Perenelle. Having such a high Flamel Index does predisposition one to longevity if not immortality.
The basic types of magical peoples are: Mages, Shapeshifters, and Vampires. Now before you think that this is a clone of some other gaming system, let's look at some details:
Mages can specialize in one of Eight Elements (Fire, Earth, Air, Water, Light, Dark, Nature and Sheol (anti-life, undead, ghosts and litches and such), as well as in one of the Eight Dimensions (Darkness, Primal, Physical, Dreaming, Celestial, Mental, Spirit and Deity). Mages can also specialize in magical skills such as Alchemy, Artifacing, and Enchantment. These are the subjects taught at Universities' magic programs.
One does not need to go to Collegium or University to be a Mage. However, if one doesn't have letters behind one's name (particularly M.M. (Masters of Magic) or Ph.D, one is not going to be taken seriously in Academic society, and one isn't going to be able to get the high paying magical engineering jobs. The Magic Academic society looks on other mages as lazy people who dabble at magic, and most of the self-taught magicians see the Academic mages as pompous narrow-minded over-educated bafoons who have no real world experience.
There are of course other types of magic than what is taught at the Universities, however those forms of magic have not yet been identified, corroborated, tested, or canonized by the International Council of Magic yet.
Now things are not quite so contentious in the cultures of Shapeshifters. I tend to call shapeshifters of this world Therianthropes, because the word doesn't have the same implication as Shapeshifters. In this world, there are many different types of shapeshifters.
The first basic difference in shapeshifters are Totemic and Non-Totemic therianthropes. Totemic shapeshifters perform a ritual bond with a totem spirit of the form they wish to be able to take. The totemic shifter and that totem are bound together. Because of this, the mass of a totemic shapeshifter is not limited to their own mass, but rather the lower end is limited to the lesser of the two's mass, and the upper end is limited to the combination of the mass of the shifter and the manifested form of the totem. This usually gives Totemic shifters not only training in how to become said creature that the totem represents, and how to behave as said creature, but aids in the flexibility of making larger forms of the totem as well as inbetween states (such as were-creatures).
Non-totemic animal shifters have to figure out everything for themselves. They are also limited to shifting within their own mass. They can compress their matter so that they are smaller, but their mass remains the same.
Animal and creature shifters aren't the only type of shapeshifters in this world. There are plenty of shapeshifters who shapeshift within the confines of the human form.
Some use said shapeshifting to modify the properties of their body for combat purposes. Some of them use said shapeshifting to disguise their appearence. Others use said shapeshifting to take on the form and image of other people.
Shapeshifting can be done freely, within the mass constraints, and within the constraints of living matter. One could, I suppose, shapeshift into a tree. However, there are inherent dangers in such a venture.
Now when it comes to vampires, it gets a bit tricky. No one knows how vampires are created. All that is known is that the Sun weakens the magic that keeps them alive. Vampires do not have any particular bond to the vampire that accidently created them. Yes, when I say no one knows how vampires are created, I mean even the vampires themselves.
Eventually someone is going to have to figure out why vampires work the way they do, but for now it's a mystery. All living vampires have an immensely high amount of willpower or will to live. If not, they would not be alive. Furthermore, vampires are very rare. Less than 0.0001% of the Earth's population is a vampire.
People with a Flamel Index higher than 375 are also very rare. Most of the world are what some might call mundanes. Some mundanes can see magic and some can't. 25% of the world population can wield magic. Fewer still can wield magic well. This includes all Mages, Shapeshifters and Vampires.
There are some religious groups that view magical humans as being abomination. However, these magical humans do have some protection via the International Council of Magic.
And thus concludes this introduction to Bell, Book and Pistol.