Sourced from: Meiun Bellecoeur
The Quran says that the jinn are made of a smokeless and "scorching fire", but are also physical in nature, being able to interact in a tactile manner with people and objects and likewise be acted upon. The jinn, humans, and angels make up the three known sapient creations of God. Like human beings, the jinn can be good, evil, or neutrally benevolent and hence have free will like humans According to the Quran, jinn have free will, and Iblīs abused this freedom in front of Allah by refusing to bow to Adam when Allah ordered angels and jinn to do so. For disobeying Allah, Iblīs was expelled from Paradise and called "Shaytān" (Satan).
There are orders or as I prefer tribes of Jinn:Please note that there are alternate spellings to many of the tribes "names" and individual Jinn will often prefer one over the other...we are a confusing lot, and intentionally so. The various weaknesses are my thought processes run wild and based solely on the mythology at hand.
*Marid: the oldest and most powerful of the Jinn who have a strong affinity for the element of water, and often reside in the elemental plane of water, desert oasis's, and deep cave grotto's. Their weakness is to fire forged steal weapons, fire magics, and weapons utilizing rubies, and gold (as they both have properties associated with heat and flame). The Marid, favor the forms of water spouts, swans, and the indistinct shadows that dart beneath the waters surface.
*Ifrit are in a class of infernal Jinn noted for their strength and cunning. An ifrit is an enormous winged creature of fire, either male or female, who lives underground and frequents ruins. Ifrits live in a society structured along ancient Arab tribal lines, complete with kings, tribes and clans. their powers center, obviously, around fire and it's destructive abilities. While ordinary weapons and forces have no power over them, they are susceptible to magic, which humans can use to kill them or to capture and enslave them Their weakness is to jade and silver based weapons (I add this to keep gem and metal weakness theme to all tribes, and it just makes sense to me).. Efreet, prefer taking on the form of metal clad warriors, or nightmarish creatures of flame. They make their homes in the old ruins of great human cultures, volcanic caves, and in the elemental plane of fire.
Shaitan these are the children of Iblīs, and are the demon equivalent to the Christian demons. Iblis was proud and considered himself superior to Adam, since Adam was made from clay and Iblis from smokeless fire. For this act of disobedience, God cursed him to Jahannam (Hell/Purgatory) for eternity, but gave him respite until the Day of Judgment, after Iblis requested it. Iblis obtained permission from God and vowed that he would use this time to lead all men and women astray to Hell. In Islamic theology, Shaytan and his minions are "whisperers", who whisper into the hearts of humans and jinn, urging them to sin. as by their nature the Shaitan are easily affected by angelic powers and true faith.
The Shaitan weakness is also the word of God or Allah. Silver and diamonds when utilized in rituals, magic and weapons can harm these creature as they represent the purity of the divine. Their powers revolve around deception, darkness and their uncanny ability to create poisons and diseases within their very being. The Shaitan, will often shapeshift into fellow travelers or camels. Shaitan prefer desolate areas where few tread, ruined temples, caves and the plane of shadow.
Ghul dwells in burial grounds areas of mass battles and death, they have no preference for any of the elemental planes, and other uninhabited places. The ghul is a fiendish type of jinni believed to be sired by Iblis A ghoul is also a desert-dwelling, shapeshifting, demon that can assume the guise of an animal, especially a hyena. It lures unwary people into the desert wastes or abandoned places to slay and devour them. The creature also preys on young children, drinks blood, steals coins, and eats the dead, then taking the form of the person most recently eaten. Ghuls also have a knack for disease, and the destructive force of the desert sands (earth magics) with which they create sandstorms, sink holes and the like to trap travelers.
Janin are the weakest of the Djinn, but they are the most likely to find humanity as more their equal if not friends. often seen as small tornado like forms in the desert, these Jinn prefer aeries, mountain peaks and high places far from the earthly bound, and the elemental plane of air. They may often be that the cool breeze that one feels if a Janin passing by. Like all Djinn they too can shapeshift, usually taking on the aspect of birds of prey. their weakness is to earth based magics, obsidian and cold forged steal weapons.
All Djinn are capable, though not always willing to grant wishes, but keep in mind that rubbing their bottle is not the method to get the ball rolling As no Genie would willing allow themselves to be captured in such a prison, and those unlucky enough to release a Djinn from captivity may not like the result of either their wish or the ire of an incensed Jinn. Furthermore, the wording of a wish is of vital importance, as the vast majority of genie's will look for loopholes and and gray areas within the poorly worded wish, and many find great joy in giving the unwanted version of a wish that is made in haste.
Djinn, being creature of magic, are also capable spell casters in their own right, but their spells should always be a reflection of their tribes core "beliefs" and "abilities" I suggest that you use restraint and defined guidelines that are established prior to your playing such potentially powerful being.
Keep in mind who and what you have created and ALWAYS play within that script, you are not a God, or Allah and remember he created you and can destroy you just as easily. Furthermore, while you are created of magic and a being of magic you are also bound to the rules of the physical (because that is what you are)...so you CAN be hurt, you Can be blinded, you CAN be captured, you CAN be fooled, etc. Translation...again you are NOT a GOD, or God like in any fashion, keep this in mind and you will find joy in playing a creature who's greatest power lies in deceptions, power plays, word swordsmanship, and political maneuvering.