This story contains spoilers for the movie Hereditary , and discusses the ending in detail. Hereditary is a horror experience like none other. It's visceral, ugly, confrontational; not for the faint of heart. There's also a lot of plot hurled at the audience in the film's breathless final act, the last 20 minutes of which are non-stop madness. It's a film so savagely scary, A24 tested audience heart rates to see how high they collectively spiked. The answer: Pretty damn high.
King Paimon appears as the ninth spirit in the Goetia ,  the twenty-second spirit in the Pseudomonarchia Daemonum ,  and in the Dictionnaire Infernal. The Goetia , Weyer, and de Plancy warn that if King Paimon appears alone, a sacrifice must be made to summon Bebal and Abalam, two kings who serve under him but do not always accompany him. These three sources state that he rules legions of spirits, some of which are of the order of Angels and the rest Powers. Critical editions of the Lesser Key of Solomon list him as a former Dominion. Practising occultist Carroll "Poke" Runyon suggests that the name ultimately derives from "a Middle Eastern Pagan Goddess", on the grounds that some manuscripts depict King Paimon as a young man riding a camel, and that the name "Paimon" purportedly meant "a tinkling sound" in an unspecified language, in turn a claimed reference to Isis. Sloane MS and the Liber Officiorum Spirituum describe him as having a "Hoarse Voice",      and those works, Weyer, and the Goetia note that he must be commanded to speak plainly,        with the Liber Officiorum Spirituum specifying that King Paimon will speak in his native language until commanded to converse in the summoner's own language. The Goetia , Weyer, Livre des Esperitz , and the Liber Officiorum Spirituum all describe him as teaching science and answering other questions. In Abramelin , King Paimon's powers include  knowledge of past and future events, clearing up doubts, making spirits appear, creating visions, acquiring and dismissing servant spirits, reanimating the dead for several years, flight, remaining underwater indefinitely, and general abilities to "make all kinds of things" and "all sorts of people and armor appear" at the behest of the magician. From Wikipedia, the free encyclopedia.
Who is King Paimon?
Paimon is a king of hell who governs legions, half of them from the Angelic Order, and half from the Order of Powers. According to Collin de Plancy , Paymon is a king of hell who governs legions, half of them from the Angelic Order, and half from the Order of Powers. If Paymon is evoked by sacrifice or libation, he may appear accompanied by Bebal and Abalam. Paris: Henri Plon, Imprimeur-Editeur, Internet Archive. Paimon is more obedient in Lucifer than other kings are.
From Discoverie of Witchcraft , Joseph H. Peterson edition: Paymon. The Spirit Paymon is of the power of the Air, the sixteenth in the ranck of Thrones, subordinate to Corban and Marbas.