You were born of Smokeless Fire, master of wastelands, walker of paths untouched by mortal feet, wielding power over the elements and mirages, hidden from the sight of the sons of Adam and daughters of Eve. You were playing tricks on them as you pleased, bargained with their magicians, to the lost you showed mercy or your cruelty, as the fancy struck you...
And then came a wise one, a powerful one, a mortal versed in the lore more esoteric than the secrets of your kind, invoking names even greater than yours and your siblings. One by one, your kind fell to cunning and power, will and words. Their essence, their spirits were captured in trinkets of bronze and iron, forever bound to serve.
Jinn are creatures of wastelands and hidden oases, mirage and deception. Neither truly spirit nor mortal flesh, they existed somewhere in between those worlds until defeated by ancient wizards and witches, and bound into talismans to forever serve heirs, the mortals who rightfully bear them. Some talismans house single jinn but most contain essences of three to five, tied into a band forever. Each jinn has a reserve of ruh, life force that drives them and powers their magic. The reserve is smaller than they had when they were free, for part of that is pooled together in the talisman, available to all the jinn sharing the same bond. Ruh slowly replenishes itself a bit every sunrise and sunset and is expended to interact with the world and perform sihr.
Despite what many myths and legends claim, jinn are not all-powerful, being limited both by their bindings, by the inherent nature of their powers, and by their knowledge of the world and understanding of the human nature.
While the jinn's hearts remain eternally bound to the talisman, they retain bodiless, intangible presences, either slumbering within the talisman or hovering around it, incapable of acting unless following orders, wishes, and desires of the heir, protecting the heir from harm, or trying to get the lost talisman back to their heir. When bodiless, the jinn can move around—the more loyal can stride farther, though even the most dutiful jinn cannot project their presence further than a ten dozens of steps or so from the talisman. If the heir issues a command or express a desire that could be fulfilled by physical action, or are endangered by circumstances that could be mitigated in such way, the jinn can channel some of the available ruh and manipulate solid objects as if physically present for a short amount of time. They can also whisper short sentences directly into the thoughts of mortals, which might offer guidance or distract. Weak-willed and impulsive individuals might even take them for their own and act on them, though it is by no means a reliant form of mind-control.
If the heir makes an explicit command, or when the jinn judge that is the most efficient way to fulfill the task given, they can channel a much greater amount of ruh and manifest it into physical bodies for themselves, usually human, though sometimes animal—mouse, bat, desert fox, cat, snake, goat, dog, hyena, jackal, desert lion, donkey, oxen, camel or similar creature common to the deserts and wastelands. Such physical form lasts until killed or dismissed by the jinn. It can move farther from the talisman than the bodiless jinn, though the distance it can safely venture away is still limited, slowly weakening when farther than that.
When the task give goes beyond simple physical activity, the jinn can resort to sihr—magic of their kind. It is within jinn's power to create objects out of thin air, or rather, raw ruh, though they are limited in complexity, shape, and composition. Creating a pebble is a child's play, forming a gold nugget isn't hard, weaving a silken gown or a splendid feast takes more time and energy. A jinn who took time and effort to understand workings of modern devices could possibly even create a car, though any electronics is far beyond capacity of jinn magic—it is simply too complex to shape, composed of too tiny pieces that would require energy exceeding capacity of even the largest bands of jinn. All jinn creations are unstable and temporary, though, remaining in existence only as long as they are close to either the heir or the talisman. Once they are past a few dozen steps away, they quickly crumble into fine sand and smoke. Another application of sihr is weaving illusions, masking the true nature of objects and creatures under the veil of magic—though like magical creations they dissolve quickly away from the talisman. Such illusions have to be anchored to specific items, changing their form and mortal perceptions of them. Finally, jinn can also use their magic to heal injuries, cure diseases, undo curses, and ward off malicious supernatural powers, though this works more energy-efficient on the heir than on other mortals, and the worst illness, such as cancer are merely suspended while near the heir or the talisman. While jinn's healing magic can't extend the heirs' life forever, it can easily allow them to live comfortably and in good health up to human maximum lifespan of decade or two past a century, though the last years might require jinn to spend majority of their energy to upheld physical and mental well being of their masters with little to spare for other tasks.
Jinn have a number of advantages directly tied to their bond with the heir. They can always sense the heir's location, vital and emotional state, and understand whatever the heir speaks. With time, they can fine-tune their understanding of the heir's emotions and desires, reading deepest thoughts and unspoken motivation behind their wishes. While bodiless and nearby they can also speak directly into the heir's mind.
Each talisman is a trinket usually made out of metal—bronze, iron, and gold are the most popular, though not exclusive. Contrary to the legends, they rarely take forms of lamps, more often being rings, necklaces, bracelets, and statuettes. Even when made of soft gold, each talisman is much more durable than its form would suggest—while not truly indestructible, nevertheless they are unlikely to be destroyed, for it would require a molten lava or one of those new foundries that make hardest steel run like a liquid.
While destroying the talisman might be a temptation to a jinn bound to one, each jinn is inherently aware that their very essence is captured within one. To destroy one, would be to erase oneself, unmake without trace nor any chance of freedom, however trifling it would be.
Heirs are the rightful owners of the talisman. The ancient spells and enchantments that bind jinn determine the ways of inheritance of such powerful artifact. The current heir can willingly pass the talisman to another person as they please, though they must do that voluntarily and knowingly—with intent of giving the talisman away, though they don't have to know about the talisman's power ("here, take this" while giving away your backpack does not passes the inheritance of the talisman stashed inside, unless giving away the talisman was the heir's intent). The current heir can designate who is supposed to inherit the talisman after them in case of their passing. If no inheritance was specified, the first of the children, spouses, and siblings of the deceased heir who claims the talisman becomes the new heir. If there is no such close relative, the first person who claims the talisman becomes the new heir. The heir can also deliberately reject ownership of the talisman. Passing, rejecting, or claiming the ownership of the talisman has to be done deliberately and of purely own will.
One can also become the heir by defeating the current heir and claiming the talisman, though jinn are bound to attempt to protect the current heir in such situation unless he explicitly commands them to not interfere, making it an unlikely prospect.
There are certain restriction on inheritance, though. First and foremost is that only a living mortal human can be heir. Undead can't inherit or claim a talisman at all and if a legitimate heir is turned into one, the ownership of the talisman passes to the next heir or is voided until a viable heir claims it. Werebeasts are not human and can't inherit either. Magicians and other folks adept in esoteric arts can be bearers of talismans, but they are not true heirs either—they can tap energies stored within the talisman for arcane purposes, but the jinn remain bodiless and powerless to act, though they can communicate with magician-heir.
When the talisman remains unclaimed, its jinn are powerless and can't do anything—a state of boredom often even more frustrating than being commanded by a mere mortal. After some time in this state, jinn tend to fall into a dream-like fugue where they barely note the events of their surrounding and yet being burdened by passage of time. This alone makes a great motivation for most jinn to take extra care protecting their heirs from harm. The only things more dreadful to a band of jinn than spending eternity at the bottom of the sea, might be their utter annihilation in the depths of a volcano, and many would wonder if the later isn't the better option anyway.
No jinn can knowingly harm their heir, directly or indirectly, including the situation where stopping the action taken would cause harm (for example, a jinn holding a large boulder under which heir passes, can't simply drop it). They can refrain from protecting their heir but as their loyalty wanes, so does their reach around the talisman, and their ability to interpret the tasks given—as the binding enchantment restrict vestiges of their freedom even more.
The jinn have free choice if they reveal themselves to the heir of the talisman they are bound to—assuming the previous heir hadn't revealed the secret of the talisman before the inheritance. Either option has its advantages and disadvantages. A clueless heir might have wilder wishes and desires but won't bother jinn with explicit tasks. A heir in the know can be more concise and clear when it comes to issuing commands but might also ask more and more.
During their services, the jinn have to struggle with their heirs—to fulfill their orders and desires; with the world around—to protect their heirs from threats, violent and accidental; with mundane thieves, envious siblings, arcane societies, and esoteric cults who would get their hands of the talisman, which at best would involve recruiting the heir, and more likely would involve killing them, or even sacrificing them to dark spirits. They also often end struggling with the consequences of the way they fulfilled their tasks—owners of wealth they redirected to their masters, criminals they thwarted, tax collectors suspicious of display of unaccounted for luxuries...