Description: What is it, exactly, that makes the Baali so feared and loathed by other Kindred? After all, the Baali do many things that other clans do. The Baali gather groups of mortals to serve their ends just like the Toreador and Ventrue, but the Camarilla clans abhor them. The Baali enjoy killing and brutalizing others as much as the Sabbat, but even the Sabbat despise the Baali. The Baali worship Satan, demons, and other denizens of evil - ah, but this is where the vital difference lies. Most vampires are taught to fear the emissaries of Hell because demons always take more than they give; demons represent a greater evil than any vampire can attain. The Baali, however, are practically made to worship evil - their special clan discipline is eventually able to summon demons - and the devils seem to like using - I mean, working with the Baali. No one knows why this is, or when the Baali first allied themselves with evil; in fact, in the modern nights most Baali don't know much about their clan at all. All that they do know is that evil is powerful and they can bargain for some of that power.
The Baali are spread across the globe and are Embraced from every walk of life, and most of them learn that it's important to blend in. This is because the Baali aren't just outcasts among vampires - they are actively and swiftly hunted wherever they are found. The clan survives by hiding and they don't tend to gather many Baali together in one place; most Baali don't even know about each other. Sometimes a pair or a triad of Baali will work together but there is nothing resembling a clan hierarchy; the most powerful Baali present rules over the lessers. Since they need mortals for sustenance and souls, Baali tend to place themselves at the head of small devil-worshipping cults. In the modern United States these cults don't draw the attention and persecution that they used to, and they tend to remain largely unnoticed until one of the cult's crimes is uncovered. When this happens, the Baali have to be prepared to flee the area quickly, leaving everyone else behind if need be. While the cults are useful and in some cases necessary, they are often an Achilles heel to the Baali. Even their clan discipline does not draw as much attention, since many of its powers are subtle. A cult on the ten o'clock news, however, is bound to call down the hunters.
It is important to note that other clans, like the Ravnos and Gangrel, are nomadic in nature, but these clans can have gatherings without being attacked en masse. The importance of these large assemblies cannot be stressed enough. At these events, Kindred are able to catch up on the latest news, share information, history, disciplines, and so forth. While many Gangrel and Ravnos are careful and suspicious of others, they tend to open up more to members of their own clans, and clan gatherings are generally considered neutral ground. The hounded Baali haven't come together in centuries and they can't trust one another at all when they meet, so a great deal of information has died out of their line. And unlike the Setites, the Baali have no homeland to call their own and defend - so when they flee from danger, they only have more enemy territory to look forward to.
Allegiances: No major sect of vampires willingly harbors the Baali, and most sects demand a swift death for any Baali uncovered in their midst. The Baali have no interest in the aims or ideals of the various sects, for that matter, but they are very interested in using others for power. The Baali infiltrate the Camarilla, the Sabbat, and the Anarchs when they can, the better to trick other vampires into service. They must be very careful when ensnaring others or else they will blow their cover and wind up on the wrong end of a full-scale hunt. While the Sabbat may be monstrous in its own way, the sect as a whole doesn't truck with demons or demon-worshippers (called infernalists). A Sabbat member must be a monster for their cause first, then a monster for themselves, but never a monster at the whim of some otherworldly being.
Founder: Most Baali do not know the history of their bloodline, but once upon a time they did. The identity of their founder has never been known. One story says that a member of the third generation (generally rumored to be Saulot, the founder of the Salubri) happened upon a devil worshipping cult one night and decided to kill them all. The bodies were tossed into a common pit and the Antediluvian deliberately bled into it before leaving, though no one knows why. Three vampires rose from the pit, each of them fourth generation: one had no name but was called "the third," while the others became known as Moloch and Nergal (both were male). Moloch and Nergal went on to sire the Baali; the whereabouts, specifics, and activities of the third are unknown.
Weakness: The Baali are uncomfortable in the presence of all religious symbols, just like vampires in Hollywood movies. They are also more vulnerable to True Faith. While True Faith is pretty rare in the modern age, it does exist, and when faced with it the Baali are in deep trouble.
Disciplines: Obfuscate, Presence, Daimoinon. Through demonic pacts, Baali might also have access to Dark Thaumaturgy.
Gaming Concerns: The Baali were originally featured, as far as I am aware, in The Storyteller's Handbook (2nd edition). They were intended to be antagonist characters in the hands of the Storyteller, not the players, so they were only given a bit of detail. A few years later they were also put in the antagonist section of the Dark Ages main book. But let's face it - Vampire is an ideal game for playing the bad guy, the worst of the worst, and the Baali have a lot of forbidden elements: demon worship, cults, the ability to curse, throw fire, make people do what they want, and so on. The Baali appealed to the players, so when White Wolf finally made Clanbook: Baali they seemed to do so with players in mind.
Still, there are a lot of ways that Baali characters can be problematic. First, it can be difficult to play any villain well, without making them seem like a cardboard cutout or - well, just silly. Experienced players should be able to do a more convincing job but any player might need a few pointers or a nudge in the right direction. It should also be noted that a Baali can be played with too much graphic detail and this can make group members uncomfortable. If a Baali is going to be a player character, the group might want to decide ahead of time how graphic their crimes should be; most groups, I'd warrant, don't want a blow by blow account of the worst crimes.
But most commonly, Baali are misused by players who believe that if they play a Baali, they will be able to do whatever they want with no pangs of conscience and no consequences. It is also likely that the player of a Baali will expect demonic interactions and demonic pacts to make their character even more powerful. For some groups, this isn't a problem because the whole group likes high-powered games. For other groups this can definitely cause problems. In such cases, the Storyteller needs only to look at the books for backup. The World of Darkness is written as a place where consequences come home to everyone, eventually, and they tend to hit hard. It is quite possible to have a vicious character in Vampire but evil is not necessarily easy; the Storyteller should keep these things in mind when facing a Baali or similar antagonistic character. There is always a bigger fish out there and everyone reaps what they sow. It is just as important to remember that demons are some of the bigger fish in the White Wolf pool and dealing with them is meant to be life-threatening, so the Storyteller should make sure that the characters pay very dearly for any demonic pacts they make.