I noticed that the Japanese script for Elden Ring is more specific about what it labels as a “demon.” I don’t speak or read Japanese, nor do I have any significant insight into the various spiritual cultures involved, so forgive me for my lack of detail—this is based on quick internet searches.
A samurai of renown from the eastern Land of Reeds. Okina means “old man,” a name he earned for the mask he wore, which depicted a snarling elder. Okina is referred to as a 修羅 (shura or asura). The word can refer to slaughter, carnage, or killing—a scene of bloodshed and violence. An asura can also be someone whose natural inclinations become destructive, growing cruel, arrogant, hateful, and thus demonic in nature. Asura are said to live by sense rather than mind, engaging in jealous conflict with heavenly beings.
The meanings can go on and on, but the core idea is of a less-than-virtuous entity, driven by conflict. Mohg, the Lord of Blood, offered Okina the life of an asura after feeling his blade—a life that endlessly thirsts for blood. That is why Okina’s cursed katana is known, at least in the Japanese script, as “mountains of corpses and rivers of blood.” Forever cutting down others, he sharpened his mind until all else lost meaning, leaving only himself and his blade—to forever be perfected.
The “Tarnished Eater.” Anastasia is referred to as a kijo—a woman who has become a demon (oni) as a result of harboring deep resentment and possessing a hideous heart. The term typically refers to female supernatural beings, often malicious in nature.
Anastasia wields a butcher’s knife, which she uses to neatly carve the human body. She has killed and eaten many Tarnished by disguising herself as a Finger Maiden (miko—a shrine maiden or young woman of divination at temples). Landing an attack with her knife also restores her health.
In Elden Ring, Shabriri was a madman whose eyes were gouged out by the people for the crime of slander. He would go on to become the most reviled man in history, as the originator of the Frenzied Flame disease—which took root in his mutilated eyes as he smiled faintly.
The name Shabriri refers to a demon of blindness, whose name means “dazzling glare”—a creature said to rest on uncovered water (such as pools or rivers) at night, afflicting those who drink from it with blindness. One way to undo or mitigate his curse is to recite an incantation in which a letter is removed from his name with each repetition.
The unrelenting katana-wielding cannibal berserker. A Rakshasa is a being born of both hunger and anger—creatures who consume human flesh and appear on battlefields with glee when slaughter is at its worst. Although myths vary, and like many popularly malicious spiritual beings, there are both “good” and “bad” kinds.
In Elden Ring, the nameless warrior woman became a Rakshasa after killing and consuming countless others ceaselessly—so much so that her armor and sword are stained red with blood and exude a vile aura. She has lost all sense of self, becoming a creature of pure instinct. Her armor and blade cut through bone at the cost of her own flesh—attack damage is greater, but so is damage received.
The Fell Omen’s title, as a fun side note, can mean something like taboo or abominable oni (demon, ghost, etc.). Morgott isn’t a demon, but it is the “folk name” by which his alter ego is known. The Fanged and Long-Tongued variants of the Imp golem are also modeled after “oni” or demons.
There are a number of other spiritual entities I may have missed, and others I won’t go into—such as faeries, marebito(Numen), kami (gods and outer gods), wraiths, rancors, those who live in death, and many more. Or Revenant herself.
But oh, how could I forget Libra? The equilibrium demon of Night. Libra is referred to as 魔 (ma), which seems to be a generic term for a demon or some kind of malicious entity. It can also refer to sorcery or magical power. He’s the demon of “tuning.”
When I look up 調律 (chōritsu), musical tuning comes up. The word itself can be broken down into “adjust/tune” and “law/discipline,” so equilibrium makes sense—it’s about balance. The Golden Order is a “law” or regulation, after all, the opposite of chaos. Libra is “tuning” it, I suppose, to incorporate elements of chaos or Frenzy.
Libra is a goat-like creature obsessed with the idea of an impartial force—hence his allegiance to the Night—and uses alchemy to create a false gold that has a holy effect but results in frenzy buildup.