But that's just it. Tokyo does NOT fit the term of supernatural. Ghouls aren't mystical. Supernatural is anything of unexplained or parallel nature and ghouls are neither. They are explained thoroughly, how they work, and they're behaviors in the manga. Nothing is left unexplained about them whatsoever.
They are just a creature that evoloved to feed on man the same way humanity evolved to eat anything. It's all scientific. There's no mystical or paranormal about the story.
Just because a creature is created for fiction doesn't make it supernatural. That's the confusion your making with the term. They are explained, personalities and habits explored and just as easily kill able with the right tool.
Sora isn't always right though.
Bye bye. o3o