They are different, non-human, non-gods, non-demon, orphans abandoned by God.
During the day, they blend in with the crowd, possessing upper-class status, beautiful and youthful looks, and graceful manners.
At night, they drink the blood of living people as a sweet drink. They have everything humans want: youth, wisdom, beauty, great strength, and eternal life.
However, once the blood supply is gone, they will turn pale and withered, and eventually die. Because they are bloodthirsty, they are called "vampires".
This is how "vampires" are described in human books. However, humans don't really understand vampires. In fact, real "vampires" are more powerful than humans think.
Concept: What is truly terrifying is not death, but eternal loneliness.