You know someone. Mabye something is a better description. He's an entity that just sort of joined your freind group, and there's something terrifying about him. Something uncanny about all the things that he does.
He's a supernatural creature of some sort, but not one of any kind that you've seen before. Faeries and all things of the gods stay clear from him, even vampires and werewolves seem to not want to be near him, and demons and ghosts all have at best a begrudging respect. He's something different.
He looks human, perfectly human. Blond hair, clear skin, bright smile, like the type of person who you'd see in a well lit ad. He's always well lit. Always photogenic. Of all the people you know who could secretly be a cryptid he seems the least likely. He's always dressed in the latest fashion, always knows the latest trends.
But there's something deeply wrong with him. At first he just seems a bit boring. He never curses. Likes the most popular movies and shows. Knows no counterculture, nothing unknown, nothing older, nothing not mainstream. It's so consistent. You think you saw him alone once and he was just standing still, not doing anything, not bothering to look like a person. It was the first time you realized he wasn't human at all.
He's very non controversial. He seems to have no religion, no political positions, perhaps no bigotry but no hatred for bigotry either. Mortal fence sitters could never hope to be what he is. It seems fine at first, but one time you were talking about politics with some people who agreed with you, but he seemed to disagree with you talking about it at all, and acusse you of starting fights.
And not to mention you remember a girl who was opening up to you and your freinds about the death of her father, and he told her to stop, told her she was making everything sad. He seems to hate everything sad. Hates sad movies. Hates sad music. Hates sad stories. It's like he sucks up all the sadness out of the room, and all the anger, and all the fear, and sometimes those things belong in some rooms.
You had a freind who said he was there when someone tried to assault them. They had been lead into someone's room at a party, and told to take of their clothing, and realized they were not permitted to leave. And he, the entity, was there, not inside the room but right outside. He didn't even know he was guarding the door, but he was. And he made it all so normal for everyone, told the person inside not to scream, that they were upsetting people, made it so nobody passing through that hallway might be upset at the assault going on outside. Perhaps an entity like him didn't truly know what he was guarding, either way he didn't care.
Eventually your freind got out of that room thanks to a poket knife. They drew the blood of the assaulters easily, such creatures are mere mortals. But the entity outside, the false human you thought was your freind, he was mad, mad at the victim for "bringing violence into a peaceful place". They stabbed him too to get out, but there was no blood inside of him, just void, like shadow given flesh, and the absence of all life incarnate.
You don't know what he is. He's not your friend anymore. There are many entities that have disguised themselves as humans. But you don't understand why one would disguise itself as someone so inhuman.