facts.

■ A goetic, extremely ancient entity. Paimon is one of the nine kings of Hell (and one of the four Cardinal Demon Kings) who serves directly under Lucifer, and is described as one of his most devoted and loyal followers.
■ The demon king of Arts, Sciences, and Knowledge, Truths, and "Secret Things", Paimon is summoned in order to grant wishes, desires, emotional support, visions, guidance, teachings, and wealth to his summoners.
■ In the grimoire he's "mainly" depicted from (The Ars Goetia from The Lesser Key of Solomon), Paimon is the only demon who requires an offering in order to summon him.
■ He has often been described as a djinn / genie in some cultures, as well as depicted as a god or goddess, a fallen angel, and many other things.
■ While his true form is likely not able to be perceived (on Earth's plane, only those who have been touched by his spirit can perceive it at all, and even then it can only be perceived as a ball of shimmering iridescent colours and lights), he does have a preferred form, and humans have detailed him in drawings and descriptions as: a man with an effeminate face (sometimes described outright as having a "woman's face"). Said to wear a "glorious crown" and ride a Dromedary camel, with a procession of spirits following behind, playing loud, cacophonous music. Paimon's voice is noted as being unable to be processed or understood by human ears unless commanded to speak in a clear language. His name is also associated with a "tinkling" sound, derived from an ancient Middle Eastern goddess. For a really apt representation of Paimon's Vibes, Colin Stetson's Reborn from the Hereditary OST is disconcertingly spot-on.
■ Despite one of his titles as the "god of mischief", Paimon must truthfully answer all questions asked of him. However, he is certainly prone to tricks and enjoys playing them himself, or watching others get up to trickery.
■ More on Paimon's history, the associations / rankings he falls under, and the grimoires he appears in can be found here.