Are the omens and hornsent the same?
short answer: no
so to explain why the omen and the hornsent are different, we first have to understand what it means to be hornsent… the hornsent aren’t a species, they’re a civilization of humans defined by the horns that grow on their bodies:
“Hornsent view the Crucible as sacred for the refinement wrought through its evolutionary gifts. Most prominently, their tangled horns.”
“Horns are sublime artifacts to hornsent, and their presence confirms the belief that they are a chosen people. Only the repeated sprouting of fresh horns can create a tangled horn, which is viewed as an irrefutable symbol of primacy.”
“The Crucible has a particularly strong influence on the beasts of the realm of shadow, causing many to grow horns despite the characteristics of their species.”
the hornsent sprout horns because the Crucible has a strong presence in the land of shadow and causes horns to sprout on creatures who don’t normally have horns… the hornsent, who revere the Crucible and its “spiral current,” saw this as a blessing and as proof that they were “a chosen people,” so they cultivated this trait. in hornsent society, the larger and more tangled your horns are, the more awesome and cool and holy you are. this is why Jori, the leader of the theocratic hornsent inquisition, has the largest, most tangled horns of all:
however, hornsent can also be born with no horns at all. this means that they'd be seen as sad and cringe. you can find hornless hornsent bound in chains, which means they might have even been a sort of slave caste... which, given what their society is like, wouldn't surprise me if that were the case:
(source: Zullie the Witch)
the omen, on paper, are the same as the hornsent — humans who were influenced by the Crucible, which caused horns to grow on their bodies. but the reason why they aren’t actually the same is because simply having horns doesn't make you hornsent. again, the hornsent are not a species, and “hornsent” isn’t a generic term for people with horns… the hornsent are a culture, a culture which the omen were very much not born into! unlike the hornsent, the omen were born into a society that sees their horns as impurities:
"A vestige of the crucible of primordial life. Born partially of devolution, it was considered a signifier of the divine in ancient times, but is now increasingly disdained as an impurity as civilization has advanced."
traits associated with the Crucible, including horns, became less and less accepted under the Golden Order as time went on... basically, the omen were seen as impure and unclean, unfit for the Erdtree's grace and excluded from society.
but there's actually something else that makes the omen fundamentally different from the hornsent... they're referred to as having "accursed blood"?
"Warped blade of shifting hue used by Morgott, the Omen King. The accursed blood that Morgott recanted and sealed away reformed into this blade."
"The mother of truth craves wounds. When Mohg stood before her, deep underground, his accursed blood erupted with fire, and he was besotted with the defilement that he was born into."
"Trident of Mohg, Lord of Blood. A sacred spear that will come to symbolize his dynasty. As well as serving as a weapon, it is an instrument of communion with an outer god who bestows power upon accursed blood."
it seems that there is something inherently different about omen blood that doesn't seem to be the case with the hornsent? omen can also innately produce a black-brown flame, which we never see any hornsent enemies do (pretty sure the inquisitors' fire is just normal fire from their candles). INTERESTINGLY, there's two items from the base game, the Omen Bairn and the Regal Omen Bairn, that produce these brown-flame wraiths... but a similar item from the DLC, the Horned Bairn, produces "vengeful spirits" that are pale and colorless!!
it's almost like the wraiths produced by the omen are "unclean" compared to the hornsent ones!
so I think this pretty definitively proves there's something more going on with the omen? but why is this the case?? Dung Eater's ending makes me think that the omen might be "cursed" simply because their existence is incompatible with the Order under the Erdtree...
"Curse grown on a corpse killed and defiled by the Dung Eater. A tender pox afflicted with omen horns. The Dung Eater cultivates the seedbed curse on corpses. By doing so he prevents dead souls returning to the Erdtree, leaving them forever cursed."
"Loathsome rune gestated by the Dung Eater. Used to restore the fractured Elden Ring when brandished by the Elden Lord. The reviled curse will last eternally, and the world's children, grandchildren, and every generation hence, will be its pustules. If Order is defiled entirely, defilement is defilement no more, and for every curse, a cursed blessing."
but there's also the theory that the omen curse was actually created by the dying hornsent as revenge upon their attackers... Hornsent Grandam says this when attacked:
"A curse upon thee, rotten miscreant. A curse upon the strumpet's progeny, upon Marika's children each and all. The curse of the omen shall strike thee down... In the form of the sacred beast's ire. May the curse strike thee… To the very last..."
she specifically calls it the "curse of the omen!" the one thing that makes me question this theory though is that she also says "in the form of the sacred beast's ire," and we know the divine beast's ire takes the form of storms... nothing like anything the omen do. an interesting theory nonetheless!
anyway TL;DR, the hornsent and the omen are different because 1. the hornsent are a culture (not a generic name for horned people), and the omen were specifically born under the Erdtree's Order, and 2. the omen are tangibly "cursed," but the hornsent are not
