The closest they are to any race in here would be vampires. Ghouls have eyes that can turn red and usually turn red in front of their only food source, humans. Their diet is literally eating humans. Their power can only activate when their eyes are red which their powers can vary from red tails that can stab through a person to red wings that spray shards. It is also unheard of that a half human half ghoul would ever be born due to the low rate of even conceiving said child never mind it actually living. They never live because they physically can't. Though there are made half ghouls who's biggest trade mark is their one red eye instead of two.

That's pretty much the jist on ghouls.