I’m looking at this Wikipedia entry https://en.m.wikipedia.org/wiki/List_of_theological_demons and there are a lot of demons categorized as being part of Christian demonology. However, many of them usually originate from the Ars Goetia, and in turn originate from other grimoires. Many of these, as far as my knowledge goes, are not mentioned in the Bible. The author himself has said that none of it exists and people who believe in it are delusional. So, my question is how are these related to Christianity? Is it just Wikipedia making a mistake? Even so, I’ve seen some Christians saying these grimoires are real and sinful, which is confusing because most of these demons are never named anywhere but in spell books and encyclopedias.
Going to recycled an older answer here:
Many of the "list of spirits" you see in occult tradition are derived, ultimately, from Solomonic grimoires - these in turn derive from a popular tradition, not contained in the Septuagint (the Koine Greek translation of the Jewish Old Testament), which attributed the Biblical King Solomon as a great magician. We can get an idea of this "uncanonical" tradition in Josephus' Antiquities of the Jews (~ 1st century AD):
God also enabled him to learn that skill which expels demons: which is a science useful, and sanative to men. He composed such incantations also by which distempers are alleviated. And he left behind him the manner of using exorcisms; by which they drive away demons; so that they never return: and this method of cure is of great force unto this day. For I have seen a certain man of my own country, whose name was Eleazar, releasing people that were demoniacal in the presence of Vespasian, and his sons, and his Captains, and the whole multitude of his soldiers: the manner of the cure was this: he put a ring that had a root of one of those sorts mentioned by Solomon to the nostrils of the demoniack: after which he drew out the demon through his nostrils: and when the man fell down immediately, he abjured him to return into him no more: making still mention of Solomon, and reciting the incantations which he composed. And when Eleazar would persuade and demonstrate to the spectators that he had such a power, he set a little way off a cup or basin full of water, and commanded the demon, as he went out of the man, to overturn it; and thereby to let the spectators know that he had left the man. And when this was done, the skill and wisdom of Solomon was shewed very manifestly. For which reason it is, that all men may know the vastness of Solomon’s abilities, and how he was beloved of God, and that the extraordinary virtues of every kind with which this King was endowed, may not be unknown to any people under the sun; for this reason, I say, it is, that we have proceeded to speak so largely of these matters.
The main takeaway here is that before Christianity ever comes onto the scene as a Jewish sect, Jewish tradition included ideas like spirits, angels, possession, and exorcism. Nor were they alone, as similar concepts can be seen in Zoroastrianism, Manichaeism, the Yazidi faith, Gnosticism...and eventually the various expressions of Christianity and Islam. As Christianity developed, then, it did so with some of these traditions - both those that would be "canonical" and those that would become "uncanonical" - as a part of their heritage, and they would influence both the popular conception of magic.
This popular tradition eventually gave way to a written tradition, as Owen Davis covers in his Grimoires: A History of Magic Books 12-13:
The first actual magic book attributed to him, the Testament of Solomon, was written in Greek sometime during the first five centuries CE and probably originated in Babylonia or Egypt. The earliest surviving papyri excerpts from it date to the latter end of the period. [...] The Testament is essentially a tale of how demons hampered the construction of the Temple by plaguing Solomon's favourite workman. Heeding Solomon's prayers for help, the angel Michael presented to him a magical ring from God. Engraved upon it was the Seal of Solomon that had the power to bind demons, and was depicted in later grimoires as variously a pentagram, hexagram, or circular symbol, while in Russia it was associated with the SATOR AREPO word square. [...] Through the power of the ring, thirty-six or more demons were compelled to appear and identify themselves to Solomon, telling him their evil powers, and how they could be controlled by writing down certain words. So the demon Autothith stated that he caused grudges and fighting but could be banished by writing sown 'Alpha' and 'Omega', the First and the Last.
This is essentially the starting point for the "lists of spirits" in the Western grimoire tradition, with examples such as the Ars Notaria ("Notary Arts", c. 14th century) and Clavicula Solomonis ("Key of Solomon", 15th century), both Solomonic grimoires, being especially notable and influential examples (the Clavicula also contains a section entitled "Ars Notaria," and the chapter "Ars Goetia" is the origin of "Goetia" or "Goetic" ceremonial magic). One important aspect that Davies also is careful to address (55):
It is important to point out that in the manuscript grimoire tradition few works are ever quite the same. There was no founding text, no print template for the Clavicule for instance. Over the generations copyists added their own personal touches, taking bits out, adding information from other sources. Apart from the rare cases where copies were kept by the authorities rather than burned, whenever the Clavicule or other well-known grimoire is mentioned in a trial record we usually have little idea as to what it contained or looked like. Some clearly followed the template of the learned medieval examples. Others might have the name of Solomon on them but were basically magic scrapbooks, compilations of practical magic for dealing with witches, causing rain, seducing women, and the like, culled form manuals of exorcisms, orations, prayers, and oral sources of knowledge.
The Dictionnaire Infernal (1818) by Jacques Auguste Simon Collin de Plancy is a much later work than these manuscript lists of spirits; it's a print book, part of a 19th century enthusiasm for the occult, and is not specifically a grimoire but a reference work. De Plancy drew on the medieval grimoire tradition in composing the Dictionnaire, but it was more of an example of the Enlightenment desire to categorize knowledge than an actual work intended to aid in the conjuring of spirits, hence why folks like Michelle Belanger in The Dictionary of Demons call him a demonographer rather than a demonologist; de Plancy's work is thorough or accessible enough that it influenced turn-of-the-century writers like A. E. Waite, Lewis Spence, and Aleister Crowley, who drew on de Plancy as a resource in writing their own works - both "practical" and academic.
It's difficult to answer your question much further because of the long span of time and vast geography involved - the religious and historical underpinnings vary according to each work and its context, but the basic idea of a list of spirits (be they angels, demons, or other) is a very old one in the Western grimoire tradition, and its origin in part comes from these sidereal traditions that existed alongside but apart from the Biblical "canon" of the Old and New Testament. If you want to get an idea of the diversity of descriptions of these spirits, grimoire scholar Dan Harms did a blog series called Spirits in the Library a couple years back which makes for fun and informative reading.