The "first demon" depends on the lore: in Demon Slayer, it's Muzan Kibutsuji, accidentally created from a cure; in Abrahamic/Pop Culture (like Supernatural), it's often Lilith, Adam's first wife; while in broader mythology, ancient beings like Leviathan (Hebrew) or primordial figures from Hindu texts (like early rakshasas) are sometimes considered first-born dark entities, but Satan/Lucifer is seen as the first fallen angel/sinner.
Lilith is the first demon. This much we know is canon. Whether or not she was originally Adam's wife is another discussion.
Lilith (/ˈlɪlɪθ/; Hebrew: לִילִית, romanized: Līlīṯ), also spelled Lilit, Lilitu, or Lilis, is a feminine figure in Mesopotamian and Jewish mythology. According to accounts in the Talmud she is a primordial she-demon. Lilith is cited as having been "banished" from the Garden of Eden for disobeying Adam.
As some of the very first demons ever created, the Princes of Hell were among the oldest and most powerful demons in all of Creation, representing the highest authority in Hell after Lucifer and Lilith. Lucifer granted them an immeasurable amount of supernatural power and made them almost impossible to kill.
The first demon that is said to have existed was Muzan. The one who turned him into a demon was a generous doctor from the Heian Period, who wanted to save Muzan from death since, at the time, he was diagnosed with a disease which would kill him before he turned twenty.
As the highest-ranking member of the Twelve Kizuki, Kokushibo is an extraordinarily powerful demon, second only to the Demon King Muzan Kibutsuji himself. He has battled countless Demon Slayers and has amassed vast experience and knowledge over his nearly 500-year-long life.
There's actually a straightforward answer to that question, but it's likely one you've never heard of: In ancient Jewish texts like the Dead Sea Scrolls, demons are the disembodied spirits of dead Nephilim giants who perished at the time of the great flood.
1. Satan (Lucifer) Satan, otherwise known as the devil, or the prince of demons, was once a beautiful angel called Lucifer, but he defied God, and subsequently suffered a fall from grace. In the book of Isaiah, God renounces Lucifer, stating, “How art thou fallen from heaven, O Lucifer, son of the morning!
They are an organization made up of the twelve strongest demons under the direct command of the Demon King, Muzan Kibutsuji. The Twelve Kizuki are divided into two groups, the six Upper Ranks and the six Lower Ranks.
Since nothing exists that God did not create, the logical conclusion is that God made the demons to be his good servants—like the angels. Demons have right beliefs about who God is; they have known about him from the beginning of their existence, even though they chose to rebel against him!
Michael and Gabriel are recognized as archangels in Judaism and Islam, and by most Christians. Raphael—mentioned in the deuterocanonical/apocryphal Book of Tobit— is also recognized as a chief angel in the Catholic, Lutheran, Anglican and Eastern Orthodox churches.
Lucifer's first sin was pride, stemming from his immense beauty, wisdom, and power, which led to coveting God's position and rebelling against His authority, a transgression described in Isaiah 14 and Ezekiel 28 as wanting to ascend to heaven and be like the Most High, resulting in his fall from heaven with other angels. This act of disobedience and self-exaltation marked the first sin in the universe, preceding humanity's fall.
Human beings are made male and female. Demons do not inhabit a physical body as human beings do. When angels or demons appear, demons are fallen cursed angels. At times, they do appear as male and female.
Demons come into existence through varying methods. Some are born naturally while some are the result of Hell's influence on a human soul. Demons can also be artificially created by binding the souls of humans, animals, or even other demons to demonic flesh or materials.
According to Jewish lore, Lilith was the first wife of Adam. Although not mentioned directly in the Bible, Lilith has been used to explain the two contradictory versions of Creation within the book of Genesis. Like Adam, Lilith was created from the dust and the earth, making them equal to one another.
Satan, also known as the devil, is the ultimate symbol of evil in Christian theology. Once a beautiful angel named Lucifer, Satan fell from grace and became the adversary of God and mankind. He tempts, accuses, and seeks to destroy.
According to the Grand Grimoire, Baal (or Bael) is the head of the infernal powers. He is also the first demon listed in Wierus's Pseudomonarchia daemonum. According to Wierus, Bael is the first king of Hell with estates in the east. He has three heads: a toad, a man, and a cat.
Lucifero is the devil residing within Dante Zogratis, one of the members of the Spade Kingdom's Dark Triad. He is known as the strongest devil and possesses immense power. Lucifero has unparalleled mana reserves, immense strength, and the ability to manipulate gravity and space.
Kokushibou ( upper rank 1 ) demon from Demon slayer artwork 🎨
Ars Goetia. The Ars Goetia, also known as the 72 Pillars, is a group comprised of seventy two demonic spirits with exemplary strength and their own armies. They are listed in the anonymously authored grimoire known as the Lesser Key of Solomon.
The underworld was home to many demonic beings, sometimes referred to as the "offspring of arali". These demons ascend from the underworld and terrorize mortals.
Okay so, we know that demons mainly eat and prefer eating human flesh/organs/blood, but that in some cases they might also eat animal flesh (like how Tamayo did in the past) and even other demons (stated to happen at the Final Selection).